From 459e289d63d720c4ae9e78bbaef3a9afe2274de2 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 2 Nov 2017 09:10:26 +0100
Subject: [PATCH 01/18] feat: setup constants

---
 packages/babylon/src/tokenizer/index.js | 25 ++++++++++++------------
 packages/babylon/src/util/charCodes.js  | 26 +++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 12 deletions(-)
 create mode 100644 packages/babylon/src/util/charCodes.js

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index fa484ed017..8c0cf7bf15 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -4,6 +4,7 @@
 
 import type { Options } from "../options";
 import type { Position } from "../util/location";
+import charCodes from "../util/charCodes";
 import {
   isIdentifierStart,
   isIdentifierChar,
@@ -328,31 +329,31 @@ export default class Tokenizer extends LocationParser {
     loop: while (this.state.pos < this.input.length) {
       const ch = this.input.charCodeAt(this.state.pos);
       switch (ch) {
-        case 32: // space
-        case 160: // non-breaking space
+        case charCodes.space:
+        case charCodes.nonBreakingSpace:
           ++this.state.pos;
           break;
 
-        case 13: // '\r' carriage return
+        case charCodes.carriageReturn:
           if (this.input.charCodeAt(this.state.pos + 1) === 10) {
             ++this.state.pos;
           }
 
-        case 10: // '\n' line feed
-        case 8232: // line separator
-        case 8233: // paragraph separator
+        case charCodes.lineFeed:
+        case charCodes.lineSeparator:
+        case charCodes.paragraphSeparator:
           ++this.state.pos;
           ++this.state.curLine;
           this.state.lineStart = this.state.pos;
           break;
 
-        case 47: // '/'
+        case charCodes.slash: // '/'
           switch (this.input.charCodeAt(this.state.pos + 1)) {
-            case 42: // '*'
+            case charCodes.asterisk: // '*'
               this.skipBlockComment();
               break;
 
-            case 47:
+            case charCodes.slash:
               this.skipLineComment(2);
               break;
 
@@ -873,7 +874,7 @@ export default class Tokenizer extends LocationParser {
         val = code - 97 + 10; // a
       } else if (code >= 65) {
         val = code - 65 + 10; // A
-      } else if (code >= 48 && code <= 57) {
+      } else if (charCodes.isIn09(code)) {
         val = code - 48; // 0-9
       } else {
         val = Infinity;
@@ -901,7 +902,7 @@ export default class Tokenizer extends LocationParser {
       this.raise(this.state.start + 2, "Expected number in radix " + radix);
 
     if (this.hasPlugin("bigInt")) {
-      if (this.input.charCodeAt(this.state.pos) === 0x6e) {
+      if (this.input.charCodeAt(this.state.pos) === charCodes.letterN) {
         // 'n'
         ++this.state.pos;
         isBigInt = true;
@@ -924,7 +925,7 @@ export default class Tokenizer extends LocationParser {
 
   readNumber(startsWithDot: boolean): void {
     const start = this.state.pos;
-    let octal = this.input.charCodeAt(start) === 0x30; // '0'
+    let octal = this.input.charCodeAt(start) === charCodes.digit0; // '0'
     let isFloat = false;
     let isBigInt = false;
 
diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
new file mode 100644
index 0000000000..b91ec1ebd9
--- /dev/null
+++ b/packages/babylon/src/util/charCodes.js
@@ -0,0 +1,26 @@
+// @flow
+
+type Char = number;
+
+const charCodes = {
+  space: 32,
+  nonBreakingSpace: 160,
+  carriageReturn: 13, // '\r'
+  lineFeed: 10, // '\n'
+  lineSeparator: 8232,
+  paragraphSeparator: 8233,
+
+  slash: 47, // '/'
+  asterisk: 42, // '*'
+
+  letterN: 110, // 'n'
+
+  digit0: 48, // '0'
+  digit9: 57, // '9'
+};
+
+export function isIn09(code: Char): boolean {
+  return code >= charCodes.digit0 && code <= charCodes.digit9;
+}
+
+export default charCodes;

From abb48507092d40ff56d5ed174744e9c5729f134a Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 2 Nov 2017 16:40:08 +0100
Subject: [PATCH 02/18] refactor: use charCodes

---
 packages/babylon/src/tokenizer/index.js | 33 ++++++++++++++-----------
 packages/babylon/src/util/charCodes.js  | 16 ++++++++++--
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 8c0cf7bf15..e1a6927593 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -364,7 +364,7 @@ export default class Tokenizer extends LocationParser {
 
         default:
           if (
-            (ch > 8 && ch < 14) ||
+            (ch > charCodes.backSpace && ch < charCodes.shiftOut) ||
             (ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch)))
           ) {
             ++this.state.pos;
@@ -528,8 +528,11 @@ export default class Tokenizer extends LocationParser {
 
     if (next === code) {
       size =
-        code === 62 && this.input.charCodeAt(this.state.pos + 2) === 62 ? 3 : 2;
-      if (this.input.charCodeAt(this.state.pos + size) === 61) {
+        code === charCodes.greaterThan &&
+        this.input.charCodeAt(this.state.pos + 2) === charCodes.greaterThan
+          ? 3
+          : 2;
+      if (this.input.charCodeAt(this.state.pos + size) === charCodes.equalsTo) {
         this.finishOp(tt.assign, size + 1);
         return;
       }
@@ -538,11 +541,11 @@ export default class Tokenizer extends LocationParser {
     }
 
     if (
-      next === 33 &&
-      code === 60 &&
+      next === charCodes.exclamationMark &&
+      code === charCodes.lessThan &&
       !this.inModule &&
-      this.input.charCodeAt(this.state.pos + 2) === 45 &&
-      this.input.charCodeAt(this.state.pos + 3) === 45
+      this.input.charCodeAt(this.state.pos + 2) === charCodes.dash &&
+      this.input.charCodeAt(this.state.pos + 3) === charCodes.dash
     ) {
       // `<!--`, an XML-style comment that should be interpreted as a line comment
       this.skipLineComment(4);
@@ -551,7 +554,7 @@ export default class Tokenizer extends LocationParser {
       return;
     }
 
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       // <= | >=
       size = 2;
     }
@@ -565,27 +568,29 @@ export default class Tokenizer extends LocationParser {
     if (next === 61) {
       this.finishOp(
         tt.equality,
-        this.input.charCodeAt(this.state.pos + 2) === 61 ? 3 : 2,
+        this.input.charCodeAt(this.state.pos + 2) === charCodes.equalsTo
+          ? 3
+          : 2,
       );
       return;
     }
-    if (code === 61 && next === 62) {
+    if (code === charCodes.equalsTo && next === charCodes.greaterThan) {
       // '=>'
       this.state.pos += 2;
       this.finishToken(tt.arrow);
       return;
     }
-    this.finishOp(code === 61 ? tt.eq : tt.bang, 1);
+    this.finishOp(code === charCodes.equalsTo ? tt.eq : tt.bang, 1);
   }
 
   readToken_question(): void {
     // '?'
     const next = this.input.charCodeAt(this.state.pos + 1);
     const next2 = this.input.charCodeAt(this.state.pos + 2);
-    if (next === 63) {
+    if (next === charCodes.questionMark) {
       // '??'
       this.finishOp(tt.nullishCoalescing, 2);
-    } else if (next === 46 && !(next2 >= 48 && next2 <= 57)) {
+    } else if (next === charCodes.dot && !(next2 >= 48 && next2 <= 57)) {
       // '.' not followed by a number
       this.state.pos += 2;
       this.finishToken(tt.questionDot);
@@ -874,7 +879,7 @@ export default class Tokenizer extends LocationParser {
         val = code - 97 + 10; // a
       } else if (code >= 65) {
         val = code - 65 + 10; // A
-      } else if (charCodes.isIn09(code)) {
+      } else if (charCodes.isDigit(code)) {
         val = code - 48; // 0-9
       } else {
         val = Infinity;
diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
index b91ec1ebd9..8143320776 100644
--- a/packages/babylon/src/util/charCodes.js
+++ b/packages/babylon/src/util/charCodes.js
@@ -4,22 +4,34 @@ type Char = number;
 
 const charCodes = {
   space: 32,
+  backSpace: 8,
+  shiftOut: 14,
   nonBreakingSpace: 160,
   carriageReturn: 13, // '\r'
   lineFeed: 10, // '\n'
   lineSeparator: 8232,
   paragraphSeparator: 8233,
 
-  slash: 47, // '/'
   asterisk: 42, // '*'
+  dot: 46, // '.'
+  slash: 47, // '/'
 
   letterN: 110, // 'n'
 
   digit0: 48, // '0'
   digit9: 57, // '9'
+
+  lessThan: 60, // '<'
+  equalsTo: 61, // '='
+  greaterThan: 62, // '>'
+  questionMark: 63, // '?'
+  at: 64, // '@'
+
+  exclamationMark: 33, // '!'
+  dash: 45, // '-'
 };
 
-export function isIn09(code: Char): boolean {
+export function isDigit(code: Char): boolean {
   return code >= charCodes.digit0 && code <= charCodes.digit9;
 }
 

From b95810f4b4979273e9d1d9411c7c1d2f1935cc70 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 2 Nov 2017 17:57:58 +0100
Subject: [PATCH 03/18] refactor: switch to individual exports

---
 packages/babylon/src/tokenizer/index.js |  2 +-
 packages/babylon/src/util/charCodes.js  | 48 ++++++++++++-------------
 2 files changed, 23 insertions(+), 27 deletions(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index e1a6927593..dc3d0e2029 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -4,7 +4,7 @@
 
 import type { Options } from "../options";
 import type { Position } from "../util/location";
-import charCodes from "../util/charCodes";
+import * as charCodes from "../util/charCodes";
 import {
   isIdentifierStart,
   isIdentifierChar,
diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
index 8143320776..9c63738c4a 100644
--- a/packages/babylon/src/util/charCodes.js
+++ b/packages/babylon/src/util/charCodes.js
@@ -2,37 +2,33 @@
 
 type Char = number;
 
-const charCodes = {
-  space: 32,
-  backSpace: 8,
-  shiftOut: 14,
-  nonBreakingSpace: 160,
-  carriageReturn: 13, // '\r'
-  lineFeed: 10, // '\n'
-  lineSeparator: 8232,
-  paragraphSeparator: 8233,
+export const space = 32;
+export const backSpace = 8;
+export const shiftOut = 14;
+export const nonBreakingSpace = 160;
+export const carriageReturn = 13; // '\r'
+export const lineFeed = 10; // '\n'
+export const lineSeparator = 8232;
+export const paragraphSeparator = 8233;
 
-  asterisk: 42, // '*'
-  dot: 46, // '.'
-  slash: 47, // '/'
+export const asterisk = 42; // '*'
+export const dot = 46; // '.'
+export const slash = 47; // '/'
 
-  letterN: 110, // 'n'
+export const letterN = 110; // 'n'
 
-  digit0: 48, // '0'
-  digit9: 57, // '9'
+export const digit0 = 48; // '0'
+export const digit9 = 57; // '9'
 
-  lessThan: 60, // '<'
-  equalsTo: 61, // '='
-  greaterThan: 62, // '>'
-  questionMark: 63, // '?'
-  at: 64, // '@'
+export const lessThan = 60; // '<'
+export const equalsTo = 61; // '='
+export const greaterThan = 62; // '>'
+export const questionMark = 63; // '?'
+export const at = 64; // '@'
 
-  exclamationMark: 33, // '!'
-  dash: 45, // '-'
-};
+export const exclamationMark = 33; // '!'
+export const dash = 45; // '-'
 
 export function isDigit(code: Char): boolean {
-  return code >= charCodes.digit0 && code <= charCodes.digit9;
+  return code >= digit0 && code <= digit9;
 }
-
-export default charCodes;

From a2ed84363637ccea772c4a70dde63e160959c3a7 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 2 Nov 2017 18:14:29 +0100
Subject: [PATCH 04/18] feat: add more charCodes

---
 packages/babylon/src/tokenizer/index.js | 61 ++++++++++++++-----------
 packages/babylon/src/util/charCodes.js  | 12 ++++-
 2 files changed, 45 insertions(+), 28 deletions(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index dc3d0e2029..444a3448c2 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -27,20 +27,20 @@ import State from "./state";
 
 const forbiddenNumericSeparatorSiblings = {
   decBinOct: [
-    46, // .
-    66, // B
-    69, // E
-    79, // O
-    95, // _ (multiple separators are not allowed)
-    98, // b
-    101, // e
-    111, // o
+    charCodes.dot,
+    charCodes.letterUpperB,
+    charCodes.letterUpperE,
+    charCodes.letterUpperO,
+    charCodes.underscore, // multiple separators are not allowed
+    charCodes.letterLowerB,
+    charCodes.letterLowerE,
+    charCodes.letterLowerO,
   ],
   hex: [
-    46, // .
-    88, // X
-    95, // _ (multiple separators are not allowed)
-    120, // x
+    charCodes.dot,
+    charCodes.letterUpperX,
+    charCodes.underscore, // multiple separators are not allowed
+    charCodes.letterLowerX,
   ],
 };
 
@@ -72,17 +72,17 @@ allowedNumericSeparatorSiblings.hex = [
   ...allowedNumericSeparatorSiblings.dec,
   // A - F
   65,
-  66,
+  charCodes.letterUpperB,
   67,
   68,
-  69,
+  charCodes.letterUpperE,
   70,
   // a - f
   97,
-  98,
+  charCodes.letterLowerB,
   99,
   100,
-  101,
+  charCodes.letterLowerE,
   102,
 ];
 
@@ -407,8 +407,7 @@ export default class Tokenizer extends LocationParser {
     }
 
     const next2 = this.input.charCodeAt(this.state.pos + 2);
-    if (next === 46 && next2 === 46) {
-      // 46 = dot '.'
+    if (next === charCodes.dot && next2 === charCodes.dot) {
       this.state.pos += 3;
       this.finishToken(tt.ellipsis);
     } else {
@@ -621,7 +620,7 @@ export default class Tokenizer extends LocationParser {
       // The interpretation of a dot depends on whether it is followed
       // by a digit or another two dots.
 
-      case 46: // '.'
+      case charCodes.dot:
         this.readToken_dot();
         return;
 
@@ -697,17 +696,26 @@ export default class Tokenizer extends LocationParser {
         // '0'
         const next = this.input.charCodeAt(this.state.pos + 1);
         // '0x', '0X' - hex number
-        if (next === 120 || next === 88) {
+        if (
+          next === charCodes.letterLowerX ||
+          next === charCodes.letterUpperX
+        ) {
           this.readRadixNumber(16);
           return;
         }
         // '0o', '0O' - octal number
-        if (next === 111 || next === 79) {
+        if (
+          next === charCodes.letterLowerO ||
+          next === charCodes.letterUpperO
+        ) {
           this.readRadixNumber(8);
           return;
         }
         // '0b', '0B' - binary number
-        if (next === 98 || next === 66) {
+        if (
+          next === charCodes.letterLowerB ||
+          next === charCodes.letterUpperB
+        ) {
           this.readRadixNumber(2);
           return;
         }
@@ -856,7 +864,7 @@ export default class Tokenizer extends LocationParser {
       if (this.hasPlugin("numericSeparator")) {
         const prev = this.input.charCodeAt(this.state.pos - 1);
         const next = this.input.charCodeAt(this.state.pos + 1);
-        if (code === 95) {
+        if (code === charCodes.underscore) {
           if (allowedSiblings.indexOf(next) === -1) {
             this.raise(this.state.pos, "Invalid or unexpected token");
           }
@@ -907,7 +915,7 @@ export default class Tokenizer extends LocationParser {
       this.raise(this.state.start + 2, "Expected number in radix " + radix);
 
     if (this.hasPlugin("bigInt")) {
-      if (this.input.charCodeAt(this.state.pos) === charCodes.letterN) {
+      if (this.input.charCodeAt(this.state.pos) === charCodes.letterLowerN) {
         // 'n'
         ++this.state.pos;
         isBigInt = true;
@@ -1120,8 +1128,7 @@ export default class Tokenizer extends LocationParser {
         return "\n"; // 'n' -> '\n'
       case 114:
         return "\r"; // 'r' -> '\r'
-      case 120: {
-        // 'x'
+      case charCodes.letterLowerX: {
         const code = this.readHexChar(2, throwOnInvalid);
         return code === null ? null : String.fromCharCode(code);
       }
@@ -1132,7 +1139,7 @@ export default class Tokenizer extends LocationParser {
       }
       case 116:
         return "\t"; // 't' -> '\t'
-      case 98:
+      case charCodes.letterLowerB:
         return "\b"; // 'b' -> '\b'
       case 118:
         return "\u000b"; // 'v' -> '\u000b'
diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
index 9c63738c4a..8ea99ea1c2 100644
--- a/packages/babylon/src/util/charCodes.js
+++ b/packages/babylon/src/util/charCodes.js
@@ -14,8 +14,18 @@ export const paragraphSeparator = 8233;
 export const asterisk = 42; // '*'
 export const dot = 46; // '.'
 export const slash = 47; // '/'
+export const underscore = 95; // '_'
 
-export const letterN = 110; // 'n'
+export const letterUpperB = 66; // 'B'
+export const letterUpperE = 69; // 'E'
+export const letterUpperO = 79; // 'O'
+export const letterUpperX = 88; // 'X'
+
+export const letterLowerN = 110; // 'n'
+export const letterLowerB = 98; // 'b'
+export const letterLowerE = 101; // 'e'
+export const letterLowerO = 111; // 'o'
+export const letterLowerX = 120; // 'x'
 
 export const digit0 = 48; // '0'
 export const digit9 = 57; // '9'

From 8b206b2c3b63bea108c065683001d449e28bc51c Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 2 Nov 2017 20:13:44 +0100
Subject: [PATCH 05/18] feat: generate charCodes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Vim 🖤
---
 packages/babylon/src/tokenizer/index.js |  62 +++++++-------
 packages/babylon/src/util/charCodes.js  | 103 +++++++++++++++++++-----
 2 files changed, 113 insertions(+), 52 deletions(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 444a3448c2..863fef0ef6 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -28,26 +28,26 @@ import State from "./state";
 const forbiddenNumericSeparatorSiblings = {
   decBinOct: [
     charCodes.dot,
-    charCodes.letterUpperB,
-    charCodes.letterUpperE,
-    charCodes.letterUpperO,
+    charCodes.uppercaseB,
+    charCodes.uppercaseE,
+    charCodes.uppercaseO,
     charCodes.underscore, // multiple separators are not allowed
-    charCodes.letterLowerB,
-    charCodes.letterLowerE,
-    charCodes.letterLowerO,
+    charCodes.lowercaseB,
+    charCodes.lowercaseE,
+    charCodes.lowercaseO,
   ],
   hex: [
     charCodes.dot,
-    charCodes.letterUpperX,
+    charCodes.uppercaseX,
     charCodes.underscore, // multiple separators are not allowed
-    charCodes.letterLowerX,
+    charCodes.lowercaseX,
   ],
 };
 
 const allowedNumericSeparatorSiblings = {};
 allowedNumericSeparatorSiblings.bin = [
   // 0 - 1
-  48,
+  charCodes.digit0,
   49,
 ];
 allowedNumericSeparatorSiblings.oct = [
@@ -64,7 +64,7 @@ allowedNumericSeparatorSiblings.dec = [
   // 0 - 9
   ...allowedNumericSeparatorSiblings.oct,
   56,
-  57,
+  charCodes.digit9,
 ];
 
 allowedNumericSeparatorSiblings.hex = [
@@ -72,17 +72,17 @@ allowedNumericSeparatorSiblings.hex = [
   ...allowedNumericSeparatorSiblings.dec,
   // A - F
   65,
-  charCodes.letterUpperB,
+  charCodes.uppercaseB,
   67,
   68,
-  charCodes.letterUpperE,
+  charCodes.uppercaseE,
   70,
   // a - f
   97,
-  charCodes.letterLowerB,
+  charCodes.lowercaseB,
   99,
   100,
-  charCodes.letterLowerE,
+  charCodes.lowercaseE,
   102,
 ];
 
@@ -401,7 +401,7 @@ export default class Tokenizer extends LocationParser {
   //
   readToken_dot(): void {
     const next = this.input.charCodeAt(this.state.pos + 1);
-    if (next >= 48 && next <= 57) {
+    if (next >= charCodes.digit0 && next <= charCodes.digit9) {
       this.readNumber(true);
       return;
     }
@@ -589,7 +589,10 @@ export default class Tokenizer extends LocationParser {
     if (next === charCodes.questionMark) {
       // '??'
       this.finishOp(tt.nullishCoalescing, 2);
-    } else if (next === charCodes.dot && !(next2 >= 48 && next2 <= 57)) {
+    } else if (
+      next === charCodes.dot &&
+      !(next2 >= charCodes.digit0 && next2 <= charCodes.digit9)
+    ) {
       // '.' not followed by a number
       this.state.pos += 2;
       this.finishToken(tt.questionDot);
@@ -692,30 +695,21 @@ export default class Tokenizer extends LocationParser {
         this.finishToken(tt.backQuote);
         return;
 
-      case 48: {
+      case charCodes.digit0: {
         // '0'
         const next = this.input.charCodeAt(this.state.pos + 1);
         // '0x', '0X' - hex number
-        if (
-          next === charCodes.letterLowerX ||
-          next === charCodes.letterUpperX
-        ) {
+        if (next === charCodes.lowercaseX || next === charCodes.uppercaseX) {
           this.readRadixNumber(16);
           return;
         }
         // '0o', '0O' - octal number
-        if (
-          next === charCodes.letterLowerO ||
-          next === charCodes.letterUpperO
-        ) {
+        if (next === charCodes.lowercaseO || next === charCodes.uppercaseO) {
           this.readRadixNumber(8);
           return;
         }
         // '0b', '0B' - binary number
-        if (
-          next === charCodes.letterLowerB ||
-          next === charCodes.letterUpperB
-        ) {
+        if (next === charCodes.lowercaseB || next === charCodes.uppercaseB) {
           this.readRadixNumber(2);
           return;
         }
@@ -730,7 +724,7 @@ export default class Tokenizer extends LocationParser {
       case 54:
       case 55:
       case 56:
-      case 57: // 1-9
+      case charCodes.digit9: // 1-9
         this.readNumber(false);
         return;
 
@@ -888,7 +882,7 @@ export default class Tokenizer extends LocationParser {
       } else if (code >= 65) {
         val = code - 65 + 10; // A
       } else if (charCodes.isDigit(code)) {
-        val = code - 48; // 0-9
+        val = code - charCodes.digit0; // 0-9
       } else {
         val = Infinity;
       }
@@ -1128,7 +1122,7 @@ export default class Tokenizer extends LocationParser {
         return "\n"; // 'n' -> '\n'
       case 114:
         return "\r"; // 'r' -> '\r'
-      case charCodes.letterLowerX: {
+      case charCodes.lowercaseX: {
         const code = this.readHexChar(2, throwOnInvalid);
         return code === null ? null : String.fromCharCode(code);
       }
@@ -1139,7 +1133,7 @@ export default class Tokenizer extends LocationParser {
       }
       case 116:
         return "\t"; // 't' -> '\t'
-      case charCodes.letterLowerB:
+      case charCodes.lowercaseB:
         return "\b"; // 'b' -> '\b'
       case 118:
         return "\u000b"; // 'v' -> '\u000b'
@@ -1152,7 +1146,7 @@ export default class Tokenizer extends LocationParser {
         ++this.state.curLine;
         return "";
       default:
-        if (ch >= 48 && ch <= 55) {
+        if (ch >= charCodes.digit0 && ch <= 55) {
           const codePos = this.state.pos - 1;
           // $FlowFixMe
           let octalStr = this.input
diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
index 8ea99ea1c2..3d2b99bb5c 100644
--- a/packages/babylon/src/util/charCodes.js
+++ b/packages/babylon/src/util/charCodes.js
@@ -14,30 +14,97 @@ export const paragraphSeparator = 8233;
 export const asterisk = 42; // '*'
 export const dot = 46; // '.'
 export const slash = 47; // '/'
-export const underscore = 95; // '_'
-
-export const letterUpperB = 66; // 'B'
-export const letterUpperE = 69; // 'E'
-export const letterUpperO = 79; // 'O'
-export const letterUpperX = 88; // 'X'
-
-export const letterLowerN = 110; // 'n'
-export const letterLowerB = 98; // 'b'
-export const letterLowerE = 101; // 'e'
-export const letterLowerO = 111; // 'o'
-export const letterLowerX = 120; // 'x'
-
+export const dash = 45; // '-'
+export const exclamationMark = 33; // '!'
+export const quotationMark = 34; // '"'
+export const numberSign = 35; // '#'
+export const dollarSign = 36; // '$'
+export const percentSign = 37; // '%'
+export const ampersand = 38; // '&'
+export const apostrophe = 39; // '''
+export const leftParenthesis = 40; // '('
+export const rightParenthesis = 41; // ')'
+export const plusSign = 43; // '+'
+export const comma = 44; // ','
 export const digit0 = 48; // '0'
+export const digit1 = 49; // '1'
+export const digit2 = 50; // '2'
+export const digit3 = 51; // '3'
+export const digit4 = 52; // '4'
+export const digit5 = 53; // '5'
+export const digit6 = 54; // '6'
+export const digit7 = 55; // '7'
+export const digit8 = 56; // '8'
 export const digit9 = 57; // '9'
-
+export const colon = 58; // ':'
+export const semicolon = 59; // ';'
 export const lessThan = 60; // '<'
 export const equalsTo = 61; // '='
 export const greaterThan = 62; // '>'
 export const questionMark = 63; // '?'
-export const at = 64; // '@'
-
-export const exclamationMark = 33; // '!'
-export const dash = 45; // '-'
+export const atSign = 64; // '@'
+export const uppercaseA = 65; // 'A'
+export const uppercaseB = 66; // 'B'
+export const uppercaseC = 67; // 'C'
+export const uppercaseD = 68; // 'D'
+export const uppercaseE = 69; // 'E'
+export const uppercaseF = 70; // 'F'
+export const uppercaseG = 71; // 'G'
+export const uppercaseH = 72; // 'H'
+export const uppercaseI = 73; // 'I'
+export const uppercaseJ = 74; // 'J'
+export const uppercaseK = 75; // 'K'
+export const uppercaseL = 76; // 'L'
+export const uppercaseM = 77; // 'M'
+export const uppercaseN = 78; // 'N'
+export const uppercaseO = 79; // 'O'
+export const uppercaseP = 80; // 'P'
+export const uppercaseQ = 81; // 'Q'
+export const uppercaseR = 82; // 'R'
+export const uppercaseS = 83; // 'S'
+export const uppercaseT = 84; // 'T'
+export const uppercaseU = 85; // 'U'
+export const uppercaseV = 86; // 'V'
+export const uppercaseW = 87; // 'W'
+export const uppercaseX = 88; // 'X'
+export const uppercaseY = 89; // 'Y'
+export const uppercaseZ = 90; // 'Z'
+export const leftSquareBracket = 91; // '['
+export const backslash = 92; // '\ '
+export const rightSquareBracket = 93; // ']'
+export const caret = 94; // '^'
+export const underscore = 95; // '_'
+export const graveAccent = 96; // '`'
+export const lowercaseA = 97; // 'a'
+export const lowercaseB = 98; // 'b'
+export const lowercaseC = 99; // 'c'
+export const lowercaseD = 100; // 'd'
+export const lowercaseE = 101; // 'e'
+export const lowercaseF = 102; // 'f'
+export const lowercaseG = 103; // 'g'
+export const lowercaseH = 104; // 'h'
+export const lowercaseI = 105; // 'i'
+export const lowercaseJ = 106; // 'j'
+export const lowercaseK = 107; // 'k'
+export const lowercaseL = 108; // 'l'
+export const lowercaseM = 109; // 'm'
+export const lowercaseN = 110; // 'n'
+export const lowercaseO = 111; // 'o'
+export const lowercaseP = 112; // 'p'
+export const lowercaseQ = 113; // 'q'
+export const lowercaseR = 114; // 'r'
+export const lowercaseS = 115; // 's'
+export const lowercaseT = 116; // 't'
+export const lowercaseU = 117; // 'u'
+export const lowercaseV = 118; // 'v'
+export const lowercaseW = 119; // 'w'
+export const lowercaseX = 120; // 'x'
+export const lowercaseY = 121; // 'y'
+export const lowercaseZ = 122; // 'z'
+export const leftCurlyBrace = 123; // '{'
+export const verticalBar = 124; // '|'
+export const rightCurlyBrace = 125; // '}'
+export const tilde = 126; // '~'
 
 export function isDigit(code: Char): boolean {
   return code >= digit0 && code <= digit9;

From b51ac5e60a23b9b45ab19f274abf3fca66302748 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Fri, 3 Nov 2017 08:27:03 +0100
Subject: [PATCH 06/18] feat: sort by value
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Vim 🖤
---
 packages/babylon/src/util/charCodes.js | 195 ++++++++++++-------------
 1 file changed, 97 insertions(+), 98 deletions(-)

diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
index 3d2b99bb5c..f74c404939 100644
--- a/packages/babylon/src/util/charCodes.js
+++ b/packages/babylon/src/util/charCodes.js
@@ -2,110 +2,109 @@
 
 type Char = number;
 
-export const space = 32;
 export const backSpace = 8;
+export const lineFeed = 10; //  '\n'
+export const carriageReturn = 13; //  '\r'
 export const shiftOut = 14;
+export const space = 32;
+export const exclamationMark = 33; //  '!'
+export const quotationMark = 34; //  '"'
+export const numberSign = 35; //  '#'
+export const dollarSign = 36; //  '$'
+export const percentSign = 37; //  '%'
+export const ampersand = 38; //  '&'
+export const apostrophe = 39; //  '''
+export const leftParenthesis = 40; //  '('
+export const rightParenthesis = 41; //  ')'
+export const asterisk = 42; //  '*'
+export const plusSign = 43; //  '+'
+export const comma = 44; //  ','
+export const dash = 45; //  '-'
+export const dot = 46; //  '.'
+export const slash = 47; //  '/'
+export const digit0 = 48; //  '0'
+export const digit1 = 49; //  '1'
+export const digit2 = 50; //  '2'
+export const digit3 = 51; //  '3'
+export const digit4 = 52; //  '4'
+export const digit5 = 53; //  '5'
+export const digit6 = 54; //  '6'
+export const digit7 = 55; //  '7'
+export const digit8 = 56; //  '8'
+export const digit9 = 57; //  '9'
+export const colon = 58; //  ':'
+export const semicolon = 59; //  ';'
+export const lessThan = 60; //  '<'
+export const equalsTo = 61; //  '='
+export const greaterThan = 62; //  '>'
+export const questionMark = 63; //  '?'
+export const atSign = 64; //  '@'
+export const uppercaseA = 65; //  'A'
+export const uppercaseB = 66; //  'B'
+export const uppercaseC = 67; //  'C'
+export const uppercaseD = 68; //  'D'
+export const uppercaseE = 69; //  'E'
+export const uppercaseF = 70; //  'F'
+export const uppercaseG = 71; //  'G'
+export const uppercaseH = 72; //  'H'
+export const uppercaseI = 73; //  'I'
+export const uppercaseJ = 74; //  'J'
+export const uppercaseK = 75; //  'K'
+export const uppercaseL = 76; //  'L'
+export const uppercaseM = 77; //  'M'
+export const uppercaseN = 78; //  'N'
+export const uppercaseO = 79; //  'O'
+export const uppercaseP = 80; //  'P'
+export const uppercaseQ = 81; //  'Q'
+export const uppercaseR = 82; //  'R'
+export const uppercaseS = 83; //  'S'
+export const uppercaseT = 84; //  'T'
+export const uppercaseU = 85; //  'U'
+export const uppercaseV = 86; //  'V'
+export const uppercaseW = 87; //  'W'
+export const uppercaseX = 88; //  'X'
+export const uppercaseY = 89; //  'Y'
+export const uppercaseZ = 90; //  'Z'
+export const leftSquareBracket = 91; //  '['
+export const backslash = 92; //  '\    '
+export const rightSquareBracket = 93; //  ']'
+export const caret = 94; //  '^'
+export const underscore = 95; //  '_'
+export const graveAccent = 96; //  '`'
+export const lowercaseA = 97; //  'a'
+export const lowercaseB = 98; //  'b'
+export const lowercaseC = 99; //  'c'
+export const lowercaseD = 100; //  'd'
+export const lowercaseE = 101; //  'e'
+export const lowercaseF = 102; //  'f'
+export const lowercaseG = 103; //  'g'
+export const lowercaseH = 104; //  'h'
+export const lowercaseI = 105; //  'i'
+export const lowercaseJ = 106; //  'j'
+export const lowercaseK = 107; //  'k'
+export const lowercaseL = 108; //  'l'
+export const lowercaseM = 109; //  'm'
+export const lowercaseN = 110; //  'n'
+export const lowercaseO = 111; //  'o'
+export const lowercaseP = 112; //  'p'
+export const lowercaseQ = 113; //  'q'
+export const lowercaseR = 114; //  'r'
+export const lowercaseS = 115; //  's'
+export const lowercaseT = 116; //  't'
+export const lowercaseU = 117; //  'u'
+export const lowercaseV = 118; //  'v'
+export const lowercaseW = 119; //  'w'
+export const lowercaseX = 120; //  'x'
+export const lowercaseY = 121; //  'y'
+export const lowercaseZ = 122; //  'z'
+export const leftCurlyBrace = 123; //  '{'
+export const verticalBar = 124; //  '|'
+export const rightCurlyBrace = 125; //  '}'
+export const tilde = 126; //  '~'
 export const nonBreakingSpace = 160;
-export const carriageReturn = 13; // '\r'
-export const lineFeed = 10; // '\n'
 export const lineSeparator = 8232;
 export const paragraphSeparator = 8233;
 
-export const asterisk = 42; // '*'
-export const dot = 46; // '.'
-export const slash = 47; // '/'
-export const dash = 45; // '-'
-export const exclamationMark = 33; // '!'
-export const quotationMark = 34; // '"'
-export const numberSign = 35; // '#'
-export const dollarSign = 36; // '$'
-export const percentSign = 37; // '%'
-export const ampersand = 38; // '&'
-export const apostrophe = 39; // '''
-export const leftParenthesis = 40; // '('
-export const rightParenthesis = 41; // ')'
-export const plusSign = 43; // '+'
-export const comma = 44; // ','
-export const digit0 = 48; // '0'
-export const digit1 = 49; // '1'
-export const digit2 = 50; // '2'
-export const digit3 = 51; // '3'
-export const digit4 = 52; // '4'
-export const digit5 = 53; // '5'
-export const digit6 = 54; // '6'
-export const digit7 = 55; // '7'
-export const digit8 = 56; // '8'
-export const digit9 = 57; // '9'
-export const colon = 58; // ':'
-export const semicolon = 59; // ';'
-export const lessThan = 60; // '<'
-export const equalsTo = 61; // '='
-export const greaterThan = 62; // '>'
-export const questionMark = 63; // '?'
-export const atSign = 64; // '@'
-export const uppercaseA = 65; // 'A'
-export const uppercaseB = 66; // 'B'
-export const uppercaseC = 67; // 'C'
-export const uppercaseD = 68; // 'D'
-export const uppercaseE = 69; // 'E'
-export const uppercaseF = 70; // 'F'
-export const uppercaseG = 71; // 'G'
-export const uppercaseH = 72; // 'H'
-export const uppercaseI = 73; // 'I'
-export const uppercaseJ = 74; // 'J'
-export const uppercaseK = 75; // 'K'
-export const uppercaseL = 76; // 'L'
-export const uppercaseM = 77; // 'M'
-export const uppercaseN = 78; // 'N'
-export const uppercaseO = 79; // 'O'
-export const uppercaseP = 80; // 'P'
-export const uppercaseQ = 81; // 'Q'
-export const uppercaseR = 82; // 'R'
-export const uppercaseS = 83; // 'S'
-export const uppercaseT = 84; // 'T'
-export const uppercaseU = 85; // 'U'
-export const uppercaseV = 86; // 'V'
-export const uppercaseW = 87; // 'W'
-export const uppercaseX = 88; // 'X'
-export const uppercaseY = 89; // 'Y'
-export const uppercaseZ = 90; // 'Z'
-export const leftSquareBracket = 91; // '['
-export const backslash = 92; // '\ '
-export const rightSquareBracket = 93; // ']'
-export const caret = 94; // '^'
-export const underscore = 95; // '_'
-export const graveAccent = 96; // '`'
-export const lowercaseA = 97; // 'a'
-export const lowercaseB = 98; // 'b'
-export const lowercaseC = 99; // 'c'
-export const lowercaseD = 100; // 'd'
-export const lowercaseE = 101; // 'e'
-export const lowercaseF = 102; // 'f'
-export const lowercaseG = 103; // 'g'
-export const lowercaseH = 104; // 'h'
-export const lowercaseI = 105; // 'i'
-export const lowercaseJ = 106; // 'j'
-export const lowercaseK = 107; // 'k'
-export const lowercaseL = 108; // 'l'
-export const lowercaseM = 109; // 'm'
-export const lowercaseN = 110; // 'n'
-export const lowercaseO = 111; // 'o'
-export const lowercaseP = 112; // 'p'
-export const lowercaseQ = 113; // 'q'
-export const lowercaseR = 114; // 'r'
-export const lowercaseS = 115; // 's'
-export const lowercaseT = 116; // 't'
-export const lowercaseU = 117; // 'u'
-export const lowercaseV = 118; // 'v'
-export const lowercaseW = 119; // 'w'
-export const lowercaseX = 120; // 'x'
-export const lowercaseY = 121; // 'y'
-export const lowercaseZ = 122; // 'z'
-export const leftCurlyBrace = 123; // '{'
-export const verticalBar = 124; // '|'
-export const rightCurlyBrace = 125; // '}'
-export const tilde = 126; // '~'
-
 export function isDigit(code: Char): boolean {
   return code >= digit0 && code <= digit9;
 }

From 72a90cb63d806c4f1695f5c2710f0142c533a930 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Fri, 3 Nov 2017 08:51:48 +0100
Subject: [PATCH 07/18] feat: more charcodes

---
 packages/babylon/src/tokenizer/index.js | 157 +++++++++++++-----------
 1 file changed, 82 insertions(+), 75 deletions(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 863fef0ef6..8308c9c10b 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -48,22 +48,22 @@ const allowedNumericSeparatorSiblings = {};
 allowedNumericSeparatorSiblings.bin = [
   // 0 - 1
   charCodes.digit0,
-  49,
+  charCodes.digit1,
 ];
 allowedNumericSeparatorSiblings.oct = [
   // 0 - 7
   ...allowedNumericSeparatorSiblings.bin,
-  50,
-  51,
-  52,
-  53,
-  54,
-  55,
+  charCodes.digit2,
+  charCodes.digit3,
+  charCodes.digit4,
+  charCodes.digit5,
+  charCodes.digit6,
+  charCodes.digit7,
 ];
 allowedNumericSeparatorSiblings.dec = [
   // 0 - 9
   ...allowedNumericSeparatorSiblings.oct,
-  56,
+  charCodes.digit8,
   charCodes.digit9,
 ];
 
@@ -71,14 +71,14 @@ allowedNumericSeparatorSiblings.hex = [
   // 0 - 9, A - F, a - f,
   ...allowedNumericSeparatorSiblings.dec,
   // A - F
-  65,
+  charCodes.uppercaseA,
   charCodes.uppercaseB,
   67,
   68,
   charCodes.uppercaseE,
   70,
   // a - f
-  97,
+  charCodes.lowercaseA,
   charCodes.lowercaseB,
   99,
   100,
@@ -231,7 +231,7 @@ export default class Tokenizer extends LocationParser {
   readToken(code: number): void {
     // Identifier or keyword. '\uXXXX' sequences are allowed in
     // identifiers, so '\' also dispatches to that.
-    if (isIdentifierStart(code) || code === 92 /* '\' */) {
+    if (isIdentifierStart(code) || code === charCodes.backslash /* '\' */) {
       this.readWord();
     } else {
       this.getTokenFromCode(code);
@@ -425,7 +425,7 @@ export default class Tokenizer extends LocationParser {
     }
 
     const next = this.input.charCodeAt(this.state.pos + 1);
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       this.finishOp(tt.assign, 2);
     } else {
       this.finishOp(tt.slash, 1);
@@ -434,18 +434,18 @@ export default class Tokenizer extends LocationParser {
 
   readToken_mult_modulo(code: number): void {
     // '%*'
-    let type = code === 42 ? tt.star : tt.modulo;
+    let type = code === charCodes.asterisk ? tt.star : tt.modulo;
     let width = 1;
     let next = this.input.charCodeAt(this.state.pos + 1);
 
     // Exponentiation operator **
-    if (code === 42 && next === 42) {
+    if (code === charCodes.asterisk && next === charCodes.asterisk) {
       width++;
       next = this.input.charCodeAt(this.state.pos + 2);
       type = tt.exponent;
     }
 
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       width++;
       type = tt.assign;
     }
@@ -458,13 +458,16 @@ export default class Tokenizer extends LocationParser {
     const next = this.input.charCodeAt(this.state.pos + 1);
 
     if (next === code) {
-      this.finishOp(code === 124 ? tt.logicalOR : tt.logicalAND, 2);
+      this.finishOp(
+        code === charCodes.verticalBar ? tt.logicalOR : tt.logicalAND,
+        2,
+      );
       return;
     }
 
-    if (code === 124) {
+    if (code === charCodes.verticalBar) {
       // '|>'
-      if (next === 62) {
+      if (next === charCodes.greaterThan) {
         this.finishOp(tt.pipeline, 2);
         return;
       } else if (next === 125 && this.hasPlugin("flow")) {
@@ -474,18 +477,21 @@ export default class Tokenizer extends LocationParser {
       }
     }
 
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       this.finishOp(tt.assign, 2);
       return;
     }
 
-    this.finishOp(code === 124 ? tt.bitwiseOR : tt.bitwiseAND, 1);
+    this.finishOp(
+      code === charCodes.verticalBar ? tt.bitwiseOR : tt.bitwiseAND,
+      1,
+    );
   }
 
   readToken_caret(): void {
     // '^'
     const next = this.input.charCodeAt(this.state.pos + 1);
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       this.finishOp(tt.assign, 2);
     } else {
       this.finishOp(tt.bitwiseXOR, 1);
@@ -498,9 +504,9 @@ export default class Tokenizer extends LocationParser {
 
     if (next === code) {
       if (
-        next === 45 &&
+        next === charCodes.dash &&
         !this.inModule &&
-        this.input.charCodeAt(this.state.pos + 2) === 62 &&
+        this.input.charCodeAt(this.state.pos + 2) === charCodes.greaterThan &&
         lineBreak.test(this.input.slice(this.state.lastTokEnd, this.state.pos))
       ) {
         // A `-->` line comment
@@ -513,7 +519,7 @@ export default class Tokenizer extends LocationParser {
       return;
     }
 
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       this.finishOp(tt.assign, 2);
     } else {
       this.finishOp(tt.plusMin, 1);
@@ -564,7 +570,7 @@ export default class Tokenizer extends LocationParser {
   readToken_eq_excl(code: number): void {
     // '=!'
     const next = this.input.charCodeAt(this.state.pos + 1);
-    if (next === 61) {
+    if (next === charCodes.equalsTo) {
       this.finishOp(
         tt.equality,
         this.input.charCodeAt(this.state.pos + 2) === charCodes.equalsTo
@@ -653,10 +659,10 @@ export default class Tokenizer extends LocationParser {
         this.finishToken(tt.bracketR);
         return;
 
-      case 123:
+      case charCodes.leftCurlyBrace:
         if (
           this.hasPlugin("flow") &&
-          this.input.charCodeAt(this.state.pos + 1) === 124
+          this.input.charCodeAt(this.state.pos + 1) === charCodes.verticalBar
         ) {
           this.finishOp(tt.braceBarL, 2);
         } else {
@@ -690,7 +696,7 @@ export default class Tokenizer extends LocationParser {
         this.finishToken(tt.at);
         return;
 
-      case 96: // '`'
+      case charCodes.graveAccent:
         ++this.state.pos;
         this.finishToken(tt.backQuote);
         return;
@@ -716,63 +722,63 @@ export default class Tokenizer extends LocationParser {
       }
       // Anything else beginning with a digit is an integer, octal
       // number, or float.
-      case 49:
-      case 50:
-      case 51:
-      case 52:
-      case 53:
-      case 54:
-      case 55:
-      case 56:
-      case charCodes.digit9: // 1-9
+      case charCodes.digit1:
+      case charCodes.digit2:
+      case charCodes.digit3:
+      case charCodes.digit4:
+      case charCodes.digit5:
+      case charCodes.digit6:
+      case charCodes.digit7:
+      case charCodes.digit8:
+      case charCodes.digit9:
         this.readNumber(false);
         return;
 
       // Quotes produce strings.
-      case 34:
-      case 39: // '"', "'"
+      case charCodes.questionMark:
+      case charCodes.apostrophe:
         this.readString(code);
         return;
 
-      // Operators are parsed inline in tiny state machines. '=' (61) is
+      // Operators are parsed inline in tiny state machines. '=' (charCodes.equalsTo) is
       // often referred to. `finishOp` simply skips the amount of
       // characters it is given as second argument, and returns a token
       // of the type given by its first argument.
 
-      case 47: // '/'
+      case charCodes.slash:
         this.readToken_slash();
         return;
 
-      case 37:
-      case 42: // '%*'
+      case charCodes.percentSign:
+      case charCodes.asterisk:
         this.readToken_mult_modulo(code);
         return;
 
-      case 124:
-      case 38: // '|&'
+      case charCodes.verticalBar:
+      case charCodes.ampersand:
         this.readToken_pipe_amp(code);
         return;
 
-      case 94: // '^'
+      case charCodes.caret:
         this.readToken_caret();
         return;
 
-      case 43:
-      case 45: // '+-'
+      case charCodes.plusSign:
+      case charCodes.dash: // '+-'
         this.readToken_plus_min(code);
         return;
 
-      case 60:
-      case 62: // '<>'
+      case charCodes.lessThan:
+      case charCodes.greaterThan:
         this.readToken_lt_gt(code);
         return;
 
-      case 61:
-      case 33: // '=!'
+      case charCodes.equalsTo:
+      case charCodes.exclamationMark:
         this.readToken_eq_excl(code);
         return;
 
-      case 126: // '~'
+      case charCodes.tilde:
         this.finishOp(tt.tilde, 1);
         return;
     }
@@ -877,10 +883,10 @@ export default class Tokenizer extends LocationParser {
         }
       }
 
-      if (code >= 97) {
-        val = code - 97 + 10; // a
-      } else if (code >= 65) {
-        val = code - 65 + 10; // A
+      if (code >= charCodes.lowercaseA) {
+        val = code - charCodes.lowercaseA + 10; // a
+      } else if (code >= charCodes.uppercaseA) {
+        val = code - charCodes.uppercaseA + 10; // A
       } else if (charCodes.isDigit(code)) {
         val = code - charCodes.digit0; // 0-9
       } else {
@@ -941,26 +947,27 @@ export default class Tokenizer extends LocationParser {
     if (octal && this.state.pos == start + 1) octal = false; // number === 0
 
     let next = this.input.charCodeAt(this.state.pos);
-    if (next === 0x2e && !octal) {
-      // '.'
+    if (next === charCodes.dot && !octal) {
       ++this.state.pos;
       this.readInt(10);
       isFloat = true;
       next = this.input.charCodeAt(this.state.pos);
     }
 
-    if ((next === 0x45 || next === 0x65) && !octal) {
-      // 'Ee'
+    if (
+      (next === charCodes.uppercaseE || next === charCodes.lowercaseE) &&
+      !octal
+    ) {
       next = this.input.charCodeAt(++this.state.pos);
-      if (next === 0x2b || next === 0x2d) ++this.state.pos; // '+-'
+      if (next === charCodes.plusSign || next === charCodes.dash)
+        ++this.state.pos;
       if (this.readInt(10) === null) this.raise(start, "Invalid number");
       isFloat = true;
       next = this.input.charCodeAt(this.state.pos);
     }
 
     if (this.hasPlugin("bigInt")) {
-      if (next === 0x6e) {
-        // 'n'
+      if (next === charCodes.lowercaseN) {
         // disallow floats and legacy octal syntax, new style octal ("0o") is handled in this.readRadixNumber
         if (isFloat || octal) this.raise(start, "Invalid BigIntLiteral");
         ++this.state.pos;
@@ -1000,7 +1007,7 @@ export default class Tokenizer extends LocationParser {
     const ch = this.input.charCodeAt(this.state.pos);
     let code;
 
-    if (ch === 123) {
+    if (ch === charCodes.leftCurlyBrace) {
       // '{'
       const codePos = ++this.state.pos;
       code = this.readHexChar(
@@ -1033,7 +1040,7 @@ export default class Tokenizer extends LocationParser {
         this.raise(this.state.start, "Unterminated string constant");
       const ch = this.input.charCodeAt(this.state.pos);
       if (ch === quote) break;
-      if (ch === 92) {
+      if (ch === charCodes.backslash) {
         // '\'
         out += this.input.slice(chunkStart, this.state.pos);
         // $FlowFixMe
@@ -1060,12 +1067,13 @@ export default class Tokenizer extends LocationParser {
         this.raise(this.state.start, "Unterminated template");
       const ch = this.input.charCodeAt(this.state.pos);
       if (
-        ch === 96 ||
-        (ch === 36 && this.input.charCodeAt(this.state.pos + 1) === 123)
+        ch === charCodes.graveAccent ||
+        (ch === charCodes.dollarSign &&
+          this.input.charCodeAt(this.state.pos + 1) ===
+            charCodes.leftCurlyBrace)
       ) {
-        // '`', '${'
         if (this.state.pos === this.state.start && this.match(tt.template)) {
-          if (ch === 36) {
+          if (ch === charCodes.dollarSign) {
             this.state.pos += 2;
             this.finishToken(tt.dollarBraceL);
             return;
@@ -1079,7 +1087,7 @@ export default class Tokenizer extends LocationParser {
         this.finishToken(tt.template, containsInvalid ? null : out);
         return;
       }
-      if (ch === 92) {
+      if (ch === charCodes.backslash) {
         // '\'
         out += this.input.slice(chunkStart, this.state.pos);
         const escaped = this.readEscapedChar(true);
@@ -1146,14 +1154,14 @@ export default class Tokenizer extends LocationParser {
         ++this.state.curLine;
         return "";
       default:
-        if (ch >= charCodes.digit0 && ch <= 55) {
+        if (ch >= charCodes.digit0 && ch <= charCodes.digit7) {
           const codePos = this.state.pos - 1;
           // $FlowFixMe
           let octalStr = this.input
             .substr(this.state.pos - 1, 3)
             .match(/^[0-7]+/)[0];
           let octal = parseInt(octalStr, 8);
-          if (octal > 255) {
+          if (octal > 2557) {
             octalStr = octalStr.slice(0, -1);
             octal = parseInt(octalStr, 8);
           }
@@ -1208,8 +1216,7 @@ export default class Tokenizer extends LocationParser {
       const ch = this.fullCharCodeAtPos();
       if (isIdentifierChar(ch)) {
         this.state.pos += ch <= 0xffff ? 1 : 2;
-      } else if (ch === 92) {
-        // "\"
+      } else if (ch === charCodes.backslash) {
         this.state.containsEsc = true;
 
         word += this.input.slice(chunkStart, this.state.pos);

From b93800d3cbbad0ecc58dda7866446c32d1e29038 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Fri, 3 Nov 2017 09:52:19 +0100
Subject: [PATCH 08/18] fix: use charcode package

---
 packages/babylon/package.json           |   3 +-
 packages/babylon/src/tokenizer/index.js |   5 +-
 packages/babylon/src/util/charCodes.js  | 110 ------------------------
 3 files changed, 4 insertions(+), 114 deletions(-)
 delete mode 100644 packages/babylon/src/util/charCodes.js

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index 0289526ca5..bc6d49946e 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -28,7 +28,8 @@
     "rollup-plugin-babel": "^4.0.0-beta.0",
     "rollup-plugin-node-resolve": "^3.0.0",
     "rollup-watch": "^4.0.0",
-    "unicode-9.0.0": "~0.7.0"
+    "unicode-9.0.0": "~0.7.0",
+    "charcodes": "^0.0.2"
   },
   "bin": {
     "babylon": "./bin/babylon.js"
diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index b16420574a..fa4ead52c4 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -4,7 +4,7 @@
 
 import type { Options } from "../options";
 import type { Position } from "../util/location";
-import * as charCodes from "../util/charCodes";
+import * as charCodes from "charcodes";
 import {
   isIdentifierStart,
   isIdentifierChar,
@@ -916,8 +916,7 @@ export default class Tokenizer extends LocationParser {
       this.raise(this.state.start + 2, "Expected number in radix " + radix);
 
     if (this.hasPlugin("bigInt")) {
-      if (this.input.charCodeAt(this.state.pos) === charCodes.letterLowerN) {
-        // 'n'
+      if (this.input.charCodeAt(this.state.pos) === charCodes.lowercaseN) {
         ++this.state.pos;
         isBigInt = true;
       }
diff --git a/packages/babylon/src/util/charCodes.js b/packages/babylon/src/util/charCodes.js
deleted file mode 100644
index f74c404939..0000000000
--- a/packages/babylon/src/util/charCodes.js
+++ /dev/null
@@ -1,110 +0,0 @@
-// @flow
-
-type Char = number;
-
-export const backSpace = 8;
-export const lineFeed = 10; //  '\n'
-export const carriageReturn = 13; //  '\r'
-export const shiftOut = 14;
-export const space = 32;
-export const exclamationMark = 33; //  '!'
-export const quotationMark = 34; //  '"'
-export const numberSign = 35; //  '#'
-export const dollarSign = 36; //  '$'
-export const percentSign = 37; //  '%'
-export const ampersand = 38; //  '&'
-export const apostrophe = 39; //  '''
-export const leftParenthesis = 40; //  '('
-export const rightParenthesis = 41; //  ')'
-export const asterisk = 42; //  '*'
-export const plusSign = 43; //  '+'
-export const comma = 44; //  ','
-export const dash = 45; //  '-'
-export const dot = 46; //  '.'
-export const slash = 47; //  '/'
-export const digit0 = 48; //  '0'
-export const digit1 = 49; //  '1'
-export const digit2 = 50; //  '2'
-export const digit3 = 51; //  '3'
-export const digit4 = 52; //  '4'
-export const digit5 = 53; //  '5'
-export const digit6 = 54; //  '6'
-export const digit7 = 55; //  '7'
-export const digit8 = 56; //  '8'
-export const digit9 = 57; //  '9'
-export const colon = 58; //  ':'
-export const semicolon = 59; //  ';'
-export const lessThan = 60; //  '<'
-export const equalsTo = 61; //  '='
-export const greaterThan = 62; //  '>'
-export const questionMark = 63; //  '?'
-export const atSign = 64; //  '@'
-export const uppercaseA = 65; //  'A'
-export const uppercaseB = 66; //  'B'
-export const uppercaseC = 67; //  'C'
-export const uppercaseD = 68; //  'D'
-export const uppercaseE = 69; //  'E'
-export const uppercaseF = 70; //  'F'
-export const uppercaseG = 71; //  'G'
-export const uppercaseH = 72; //  'H'
-export const uppercaseI = 73; //  'I'
-export const uppercaseJ = 74; //  'J'
-export const uppercaseK = 75; //  'K'
-export const uppercaseL = 76; //  'L'
-export const uppercaseM = 77; //  'M'
-export const uppercaseN = 78; //  'N'
-export const uppercaseO = 79; //  'O'
-export const uppercaseP = 80; //  'P'
-export const uppercaseQ = 81; //  'Q'
-export const uppercaseR = 82; //  'R'
-export const uppercaseS = 83; //  'S'
-export const uppercaseT = 84; //  'T'
-export const uppercaseU = 85; //  'U'
-export const uppercaseV = 86; //  'V'
-export const uppercaseW = 87; //  'W'
-export const uppercaseX = 88; //  'X'
-export const uppercaseY = 89; //  'Y'
-export const uppercaseZ = 90; //  'Z'
-export const leftSquareBracket = 91; //  '['
-export const backslash = 92; //  '\    '
-export const rightSquareBracket = 93; //  ']'
-export const caret = 94; //  '^'
-export const underscore = 95; //  '_'
-export const graveAccent = 96; //  '`'
-export const lowercaseA = 97; //  'a'
-export const lowercaseB = 98; //  'b'
-export const lowercaseC = 99; //  'c'
-export const lowercaseD = 100; //  'd'
-export const lowercaseE = 101; //  'e'
-export const lowercaseF = 102; //  'f'
-export const lowercaseG = 103; //  'g'
-export const lowercaseH = 104; //  'h'
-export const lowercaseI = 105; //  'i'
-export const lowercaseJ = 106; //  'j'
-export const lowercaseK = 107; //  'k'
-export const lowercaseL = 108; //  'l'
-export const lowercaseM = 109; //  'm'
-export const lowercaseN = 110; //  'n'
-export const lowercaseO = 111; //  'o'
-export const lowercaseP = 112; //  'p'
-export const lowercaseQ = 113; //  'q'
-export const lowercaseR = 114; //  'r'
-export const lowercaseS = 115; //  's'
-export const lowercaseT = 116; //  't'
-export const lowercaseU = 117; //  'u'
-export const lowercaseV = 118; //  'v'
-export const lowercaseW = 119; //  'w'
-export const lowercaseX = 120; //  'x'
-export const lowercaseY = 121; //  'y'
-export const lowercaseZ = 122; //  'z'
-export const leftCurlyBrace = 123; //  '{'
-export const verticalBar = 124; //  '|'
-export const rightCurlyBrace = 125; //  '}'
-export const tilde = 126; //  '~'
-export const nonBreakingSpace = 160;
-export const lineSeparator = 8232;
-export const paragraphSeparator = 8233;
-
-export function isDigit(code: Char): boolean {
-  return code >= digit0 && code <= digit9;
-}

From 3e34162092e12b271b629527ada7f02b81b5495a Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Tue, 7 Nov 2017 18:07:38 +0100
Subject: [PATCH 09/18] chore: bump charcode

---
 packages/babylon/package.json | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index bc6d49946e..80eb768f45 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -24,12 +24,13 @@
   },
   "devDependencies": {
     "@babel/helper-fixtures": "7.0.0-beta.5",
+    "babel-plugin-transform-charcodes": "0.0.3-0",
+    "charcodes": "0.0.3-0",
     "rollup": "^0.50.0",
     "rollup-plugin-babel": "^4.0.0-beta.0",
     "rollup-plugin-node-resolve": "^3.0.0",
     "rollup-watch": "^4.0.0",
-    "unicode-9.0.0": "~0.7.0",
-    "charcodes": "^0.0.2"
+    "unicode-9.0.0": "~0.7.0"
   },
   "bin": {
     "babylon": "./bin/babylon.js"

From f3f005c67e2cbe2947174d9ba5b2a874824232ef Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Tue, 7 Nov 2017 19:16:04 +0100
Subject: [PATCH 10/18] feat: use charcode AOT transform

---
 packages/babylon/package.json     | 4 ++--
 packages/babylon/rollup.config.js | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index 87f6cb26fe..8ce960d302 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -25,8 +25,8 @@
   "devDependencies": {
     "@babel/helper-fixtures": "7.0.0-beta.31",
     "babel-plugin-transform-for-of-as-array": "1.0.4",
-    "babel-plugin-transform-charcodes": "0.0.3-0",
-    "charcodes": "0.0.3-0",
+    "babel-plugin-transform-charcodes": "0.0.3",
+    "charcodes": "0.0.3",
     "rollup": "^0.50.0",
     "rollup-plugin-babel": "^4.0.0-beta.0",
     "rollup-plugin-node-resolve": "^3.0.0",
diff --git a/packages/babylon/rollup.config.js b/packages/babylon/rollup.config.js
index 7ed7a136b4..f627c6a860 100644
--- a/packages/babylon/rollup.config.js
+++ b/packages/babylon/rollup.config.js
@@ -24,7 +24,7 @@ export default {
         ],
         "@babel/flow",
       ],
-      plugins: ["transform-for-of-as-array"],
+      plugins: ["transform-charcodes", "transform-for-of-as-array"],
     }),
     nodeResolve(),
   ],

From cd8a869a189541e947cbd503194343ed859372cc Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Wed, 8 Nov 2017 13:20:11 +0100
Subject: [PATCH 11/18] fix: remove unwanted change

---
 packages/babylon/src/tokenizer/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 252855641d..579c682b15 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -1172,7 +1172,7 @@ export default class Tokenizer extends LocationParser {
             .substr(this.state.pos - 1, 3)
             .match(/^[0-7]+/)[0];
           let octal = parseInt(octalStr, 8);
-          if (octal > 2557) {
+          if (octal > 255) {
             octalStr = octalStr.slice(0, -1);
             octal = parseInt(octalStr, 8);
           }

From 6b417a8ecb047ea479891a158cd4f2a9586382c9 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Wed, 8 Nov 2017 16:56:25 +0100
Subject: [PATCH 12/18] chore: bump charcode plugin

---
 packages/babylon/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index 8ce960d302..1663b9bd12 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -25,7 +25,7 @@
   "devDependencies": {
     "@babel/helper-fixtures": "7.0.0-beta.31",
     "babel-plugin-transform-for-of-as-array": "1.0.4",
-    "babel-plugin-transform-charcodes": "0.0.3",
+    "babel-plugin-transform-charcodes": "0.0.5",
     "charcodes": "0.0.3",
     "rollup": "^0.50.0",
     "rollup-plugin-babel": "^4.0.0-beta.0",

From 88c1b4ef1ce6adead64acb865d7a0bab119962ec Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 9 Nov 2017 17:13:36 +0100
Subject: [PATCH 13/18] feat: more charcodes

---
 packages/babylon/package.json           |   4 +-
 packages/babylon/src/tokenizer/index.js | 120 ++++++++++++------------
 2 files changed, 63 insertions(+), 61 deletions(-)

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index 1663b9bd12..6df0578357 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -25,8 +25,8 @@
   "devDependencies": {
     "@babel/helper-fixtures": "7.0.0-beta.31",
     "babel-plugin-transform-for-of-as-array": "1.0.4",
-    "babel-plugin-transform-charcodes": "0.0.5",
-    "charcodes": "0.0.3",
+    "babel-plugin-transform-charcodes": "0.0.7",
+    "charcodes": "0.0.6",
     "rollup": "^0.50.0",
     "rollup-plugin-babel": "^4.0.0-beta.0",
     "rollup-plugin-node-resolve": "^3.0.0",
diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 579c682b15..7a747d6b3c 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -53,6 +53,7 @@ allowedNumericSeparatorSiblings.bin = [
 allowedNumericSeparatorSiblings.oct = [
   // 0 - 7
   ...allowedNumericSeparatorSiblings.bin,
+
   charCodes.digit2,
   charCodes.digit3,
   charCodes.digit4,
@@ -63,6 +64,7 @@ allowedNumericSeparatorSiblings.oct = [
 allowedNumericSeparatorSiblings.dec = [
   // 0 - 9
   ...allowedNumericSeparatorSiblings.oct,
+
   charCodes.digit8,
   charCodes.digit9,
 ];
@@ -70,20 +72,20 @@ allowedNumericSeparatorSiblings.dec = [
 allowedNumericSeparatorSiblings.hex = [
   // 0 - 9, A - F, a - f,
   ...allowedNumericSeparatorSiblings.dec,
-  // A - F
+
   charCodes.uppercaseA,
   charCodes.uppercaseB,
-  67,
-  68,
+  charCodes.uppercaseC,
+  charCodes.uppercaseD,
   charCodes.uppercaseE,
-  70,
-  // a - f
+  charCodes.uppercaseF,
+
   charCodes.lowercaseA,
   charCodes.lowercaseB,
-  99,
-  100,
+  charCodes.lowercaseC,
+  charCodes.lowercaseD,
   charCodes.lowercaseE,
-  102,
+  charCodes.lowercaseF,
 ];
 
 // Object type used to represent tokens. Note that normally, tokens
@@ -115,7 +117,7 @@ function codePointToString(code: number): string {
   } else {
     return String.fromCharCode(
       ((code - 0x10000) >> 10) + 0xd800,
-      ((code - 0x10000) & 1023) + 0xdc00,
+      ((code - 0x10000) & charCodes.lowercaseF) + 0xdc00,
     );
   }
 }
@@ -302,10 +304,10 @@ export default class Tokenizer extends LocationParser {
     let ch = this.input.charCodeAt((this.state.pos += startSkip));
     if (this.state.pos < this.input.length) {
       while (
-        ch !== 10 &&
-        ch !== 13 &&
-        ch !== 8232 &&
-        ch !== 8233 &&
+        ch !== charCodes.lineFeed &&
+        ch !== charCodes.carriageReturn &&
+        ch !== charCodes.lineSeparator &&
+        ch !== charCodes.paragraphSeparator &&
         ++this.state.pos < this.input.length
       ) {
         ch = this.input.charCodeAt(this.state.pos);
@@ -335,7 +337,9 @@ export default class Tokenizer extends LocationParser {
           break;
 
         case charCodes.carriageReturn:
-          if (this.input.charCodeAt(this.state.pos + 1) === 10) {
+          if (
+            this.input.charCodeAt(this.state.pos + 1) === charCodes.lineFeed
+          ) {
             ++this.state.pos;
           }
 
@@ -347,9 +351,9 @@ export default class Tokenizer extends LocationParser {
           this.state.lineStart = this.state.pos;
           break;
 
-        case charCodes.slash: // '/'
+        case charCodes.slash:
           switch (this.input.charCodeAt(this.state.pos + 1)) {
-            case charCodes.asterisk: // '*'
+            case charCodes.asterisk:
               this.skipBlockComment();
               break;
 
@@ -471,7 +475,7 @@ export default class Tokenizer extends LocationParser {
       if (next === charCodes.greaterThan) {
         this.finishOp(tt.pipeline, 2);
         return;
-      } else if (next === 125 && this.hasPlugin("flow")) {
+      } else if (next === charCodes.rightCurlyBrace && this.hasPlugin("flow")) {
         // '|}'
         this.finishOp(tt.braceBarR, 2);
         return;
@@ -611,7 +615,7 @@ export default class Tokenizer extends LocationParser {
 
   getTokenFromCode(code: number): void {
     switch (code) {
-      case 35: // '#'
+      case charCodes.numberSign:
         if (
           (this.hasPlugin("classPrivateProperties") ||
             this.hasPlugin("classPrivateMethods")) &&
@@ -635,27 +639,27 @@ export default class Tokenizer extends LocationParser {
         return;
 
       // Punctuation tokens.
-      case 40:
+      case charCodes.leftParenthesis:
         ++this.state.pos;
         this.finishToken(tt.parenL);
         return;
-      case 41:
+      case charCodes.rightParenthesis:
         ++this.state.pos;
         this.finishToken(tt.parenR);
         return;
-      case 59:
+      case charCodes.semicolon:
         ++this.state.pos;
         this.finishToken(tt.semi);
         return;
-      case 44:
+      case charCodes.comma:
         ++this.state.pos;
         this.finishToken(tt.comma);
         return;
-      case 91:
+      case charCodes.leftSquareBracket:
         ++this.state.pos;
         this.finishToken(tt.bracketL);
         return;
-      case 93:
+      case charCodes.rightSquareBracket:
         ++this.state.pos;
         this.finishToken(tt.bracketR);
         return;
@@ -672,15 +676,15 @@ export default class Tokenizer extends LocationParser {
         }
         return;
 
-      case 125:
+      case charCodes.rightCurlyBrace:
         ++this.state.pos;
         this.finishToken(tt.braceR);
         return;
 
-      case 58:
+      case charCodes.colon:
         if (
           this.hasPlugin("functionBind") &&
-          this.input.charCodeAt(this.state.pos + 1) === 58
+          this.input.charCodeAt(this.state.pos + 1) === charCodes.colon
         ) {
           this.finishOp(tt.doubleColon, 2);
         } else {
@@ -689,10 +693,10 @@ export default class Tokenizer extends LocationParser {
         }
         return;
 
-      case 63:
+      case charCodes.questionMark:
         this.readToken_question();
         return;
-      case 64:
+      case charCodes.atSign:
         ++this.state.pos;
         this.finishToken(tt.at);
         return;
@@ -703,7 +707,6 @@ export default class Tokenizer extends LocationParser {
         return;
 
       case charCodes.digit0: {
-        // '0'
         const next = this.input.charCodeAt(this.state.pos + 1);
         // '0x', '0X' - hex number
         if (next === charCodes.lowercaseX || next === charCodes.uppercaseX) {
@@ -736,7 +739,7 @@ export default class Tokenizer extends LocationParser {
         return;
 
       // Quotes produce strings.
-      case charCodes.questionMark:
+      case charCodes.quotationMark:
       case charCodes.apostrophe:
         this.readString(code);
         return;
@@ -765,7 +768,7 @@ export default class Tokenizer extends LocationParser {
         return;
 
       case charCodes.plusSign:
-      case charCodes.dash: // '+-'
+      case charCodes.dash:
         this.readToken_plus_min(code);
         return;
 
@@ -887,9 +890,9 @@ export default class Tokenizer extends LocationParser {
       }
 
       if (code >= charCodes.lowercaseA) {
-        val = code - charCodes.lowercaseA + 10; // a
+        val = code - charCodes.lowercaseA + charCodes.lineFeed;
       } else if (code >= charCodes.uppercaseA) {
-        val = code - charCodes.uppercaseA + 10; // A
+        val = code - charCodes.uppercaseA + charCodes.lineFeed;
       } else if (charCodes.isDigit(code)) {
         val = code - charCodes.digit0; // 0-9
       } else {
@@ -943,7 +946,7 @@ export default class Tokenizer extends LocationParser {
 
   readNumber(startsWithDot: boolean): void {
     const start = this.state.pos;
-    let octal = this.input.charCodeAt(start) === charCodes.digit0; // '0'
+    let octal = this.input.charCodeAt(start) === charCodes.digit0;
     let isFloat = false;
     let isBigInt = false;
 
@@ -1016,7 +1019,6 @@ export default class Tokenizer extends LocationParser {
     let code;
 
     if (ch === charCodes.leftCurlyBrace) {
-      // '{'
       const codePos = ++this.state.pos;
       code = this.readHexChar(
         this.input.indexOf("}", this.state.pos) - this.state.pos,
@@ -1050,7 +1052,6 @@ export default class Tokenizer extends LocationParser {
       const ch = this.input.charCodeAt(this.state.pos);
       if (ch === quote) break;
       if (ch === charCodes.backslash) {
-        // '\'
         out += this.input.slice(chunkStart, this.state.pos);
         // $FlowFixMe
         out += this.readEscapedChar(false);
@@ -1099,7 +1100,6 @@ export default class Tokenizer extends LocationParser {
         return;
       }
       if (ch === charCodes.backslash) {
-        // '\'
         out += this.input.slice(chunkStart, this.state.pos);
         const escaped = this.readEscapedChar(true);
         if (escaped === null) {
@@ -1112,9 +1112,11 @@ export default class Tokenizer extends LocationParser {
         out += this.input.slice(chunkStart, this.state.pos);
         ++this.state.pos;
         switch (ch) {
-          case 13:
-            if (this.input.charCodeAt(this.state.pos) === 10) ++this.state.pos;
-          case 10:
+          case charCodes.carriageReturn:
+            if (this.input.charCodeAt(this.state.pos) === charCodes.lineFeed) {
+              ++this.state.pos;
+            }
+          case charCodes.lineFeed:
             out += "\n";
             break;
           default:
@@ -1137,30 +1139,31 @@ export default class Tokenizer extends LocationParser {
     const ch = this.input.charCodeAt(++this.state.pos);
     ++this.state.pos;
     switch (ch) {
-      case 110:
-        return "\n"; // 'n' -> '\n'
-      case 114:
-        return "\r"; // 'r' -> '\r'
+      case charCodes.lowercaseN:
+        return "\n";
+      case charCodes.lowercaseR:
+        return "\r";
       case charCodes.lowercaseX: {
         const code = this.readHexChar(2, throwOnInvalid);
         return code === null ? null : String.fromCharCode(code);
       }
-      case 117: {
-        // 'u'
+      case charCodes.lowercaseU: {
         const code = this.readCodePoint(throwOnInvalid);
         return code === null ? null : codePointToString(code);
       }
-      case 116:
-        return "\t"; // 't' -> '\t'
+      case charCodes.lowercaseT:
+        return "\t";
       case charCodes.lowercaseB:
-        return "\b"; // 'b' -> '\b'
-      case 118:
-        return "\u000b"; // 'v' -> '\u000b'
-      case 102:
-        return "\f"; // 'f' -> '\f'
-      case 13:
-        if (this.input.charCodeAt(this.state.pos) === 10) ++this.state.pos; // '\r\n'
-      case 10: // ' \n'
+        return "\b";
+      case charCodes.lowercaseV:
+        return "\u000b";
+      case charCodes.lowercaseF:
+        return "\f";
+      case charCodes.carriageReturn:
+        if (this.input.charCodeAt(this.state.pos) === charCodes.lineFeed) {
+          ++this.state.pos;
+        }
+      case charCodes.lineFeed:
         this.state.lineStart = this.state.pos;
         ++this.state.curLine;
         return "";
@@ -1233,8 +1236,7 @@ export default class Tokenizer extends LocationParser {
         word += this.input.slice(chunkStart, this.state.pos);
         const escStart = this.state.pos;
 
-        if (this.input.charCodeAt(++this.state.pos) !== 117) {
-          // "u"
+        if (this.input.charCodeAt(++this.state.pos) !== charCodes.lowercaseU) {
           this.raise(
             this.state.pos,
             "Expecting Unicode escape sequence \\uXXXX",

From b79e3c0e99865c5078249d09e3351cbaac503cc0 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 9 Nov 2017 18:07:10 +0100
Subject: [PATCH 14/18] fix: minor changes

---
 packages/babylon/src/tokenizer/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 7a747d6b3c..1f45a76414 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -117,7 +117,7 @@ function codePointToString(code: number): string {
   } else {
     return String.fromCharCode(
       ((code - 0x10000) >> 10) + 0xd800,
-      ((code - 0x10000) & charCodes.lowercaseF) + 0xdc00,
+      ((code - 0x10000) & 1023) + 0xdc00,
     );
   }
 }
@@ -233,7 +233,7 @@ export default class Tokenizer extends LocationParser {
   readToken(code: number): void {
     // Identifier or keyword. '\uXXXX' sequences are allowed in
     // identifiers, so '\' also dispatches to that.
-    if (isIdentifierStart(code) || code === charCodes.backslash /* '\' */) {
+    if (isIdentifierStart(code) || code === charCodes.backslash) {
       this.readWord();
     } else {
       this.getTokenFromCode(code);

From 097ff400018d237fb1bd7f04825487c43493c1de Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Sat, 11 Nov 2017 18:08:43 +0100
Subject: [PATCH 15/18] feat: more charCodes

---
 packages/babylon/src/tokenizer/index.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 1f45a76414..608a85bf79 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -369,7 +369,8 @@ export default class Tokenizer extends LocationParser {
         default:
           if (
             (ch > charCodes.backSpace && ch < charCodes.shiftOut) ||
-            (ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch)))
+            (ch >= charCodes.oghamSpaceMark &&
+              nonASCIIwhitespace.test(String.fromCharCode(ch)))
           ) {
             ++this.state.pos;
           } else {

From 186f04a3e996e68c02aa749c41849083686f84b5 Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Mon, 13 Nov 2017 13:15:32 +0100
Subject: [PATCH 16/18] feat: use charcodes in JSX plugin

---
 packages/babylon/src/plugins/jsx/index.js | 29 ++++++++++++++---------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/packages/babylon/src/plugins/jsx/index.js b/packages/babylon/src/plugins/jsx/index.js
index 9478bec17c..15444d8738 100644
--- a/packages/babylon/src/plugins/jsx/index.js
+++ b/packages/babylon/src/plugins/jsx/index.js
@@ -1,5 +1,7 @@
 // @flow
 
+import * as charCodes from "charcodes";
+
 import XHTMLEntities from "./xhtml";
 import type Parser from "../../parser";
 import { TokenType, types as tt } from "../../tokenizer/types";
@@ -84,10 +86,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         const ch = this.input.charCodeAt(this.state.pos);
 
         switch (ch) {
-          case 60: // "<"
-          case 123: // "{"
+          case charCodes.lessThan:
+          case charCodes.leftCurlyBrace:
             if (this.state.pos === this.state.start) {
-              if (ch === 60 && this.state.exprAllowed) {
+              if (ch === charCodes.lessThan && this.state.exprAllowed) {
                 ++this.state.pos;
                 return this.finishToken(tt.jsxTagStart);
               }
@@ -96,7 +98,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             out += this.input.slice(chunkStart, this.state.pos);
             return this.finishToken(tt.jsxText, out);
 
-          case 38: // "&"
+          case charCodes.ampersand:
             out += this.input.slice(chunkStart, this.state.pos);
             out += this.jsxReadEntity();
             chunkStart = this.state.pos;
@@ -118,7 +120,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       const ch = this.input.charCodeAt(this.state.pos);
       let out;
       ++this.state.pos;
-      if (ch === 13 && this.input.charCodeAt(this.state.pos) === 10) {
+      if (
+        ch === charCodes.carriageReturn &&
+        this.input.charCodeAt(this.state.pos) === charCodes.lineFeed
+      ) {
         ++this.state.pos;
         out = normalizeCRLF ? "\n" : "\r\n";
       } else {
@@ -140,8 +145,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
         const ch = this.input.charCodeAt(this.state.pos);
         if (ch === quote) break;
-        if (ch === 38) {
-          // "&"
+        if (ch === charCodes.ampersand) {
           out += this.input.slice(chunkStart, this.state.pos);
           out += this.jsxReadEntity();
           chunkStart = this.state.pos;
@@ -205,7 +209,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       const start = this.state.pos;
       do {
         ch = this.input.charCodeAt(++this.state.pos);
-      } while (isIdentifierChar(ch) || ch === 45); // "-"
+      } while (isIdentifierChar(ch) || ch === charCodes.dash);
       return this.finishToken(
         tt.jsxName,
         this.input.slice(start, this.state.pos),
@@ -513,17 +517,20 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           return this.jsxReadWord();
         }
 
-        if (code === 62) {
+        if (code === charCodes.greaterThan) {
           ++this.state.pos;
           return this.finishToken(tt.jsxTagEnd);
         }
 
-        if ((code === 34 || code === 39) && context === tc.j_oTag) {
+        if (
+          (code === charCodes.quotationMark || code === charCodes.apostrophe) &&
+          context === tc.j_oTag
+        ) {
           return this.jsxReadString(code);
         }
       }
 
-      if (code === 60 && this.state.exprAllowed) {
+      if (code === charCodes.lessThan && this.state.exprAllowed) {
         ++this.state.pos;
         return this.finishToken(tt.jsxTagStart);
       }

From 4c584ae341564ff8719e78018ec06f02ab93f4ad Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Wed, 15 Nov 2017 19:53:30 +0100
Subject: [PATCH 17/18] chore: upgrade and fix charcodes

---
 packages/babylon/package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index 6df0578357..7cff5cd493 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -25,8 +25,8 @@
   "devDependencies": {
     "@babel/helper-fixtures": "7.0.0-beta.31",
     "babel-plugin-transform-for-of-as-array": "1.0.4",
-    "babel-plugin-transform-charcodes": "0.0.7",
-    "charcodes": "0.0.6",
+    "babel-plugin-transform-charcodes": "0.0.9",
+    "charcodes": "0.0.9",
     "rollup": "^0.50.0",
     "rollup-plugin-babel": "^4.0.0-beta.0",
     "rollup-plugin-node-resolve": "^3.0.0",

From 57e2c45cbeb66e494d2caf6aa05a87d4aede90ec Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <sven.sauleau@xtuc.fr>
Date: Thu, 16 Nov 2017 09:57:20 +0100
Subject: [PATCH 18/18] chore: upgrade charcode

---
 packages/babylon/package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/babylon/package.json b/packages/babylon/package.json
index 7cff5cd493..d80eff69ae 100644
--- a/packages/babylon/package.json
+++ b/packages/babylon/package.json
@@ -25,8 +25,8 @@
   "devDependencies": {
     "@babel/helper-fixtures": "7.0.0-beta.31",
     "babel-plugin-transform-for-of-as-array": "1.0.4",
-    "babel-plugin-transform-charcodes": "0.0.9",
-    "charcodes": "0.0.9",
+    "babel-plugin-transform-charcodes": "0.0.10",
+    "charcodes": "0.0.10",
     "rollup": "^0.50.0",
     "rollup-plugin-babel": "^4.0.0-beta.0",
     "rollup-plugin-node-resolve": "^3.0.0",