babel/babylon#328 babel/babylon#205 ?. as nullPropagation. For now it only works for member access. (.? or ?.[) If the object is undefined this will return undefined. If the object on which you want to access the property is defined, the value of the propery will be given back.

2017-02-11 21:09:27 +01:00 · 2017-02-11 21:09:27 +01:00 · 1eaf01661b
commit 1eaf01661b
parent b902fe6c7b
6 changed files with 68 additions and 75 deletions
--- a/ast/spec.md
+++ b/ast/spec.md
@ -857,7 +857,7 @@ interface MemberExpression <: Expression, Pattern {
  object: Expression | Super;
  property: Expression;
  computed: boolean;
-  nullPropagation: boolean;
+  nullPropagation: boolean | null;
 }
 ```

--- a/src/parser/expression.js
+++ b/src/parser/expression.js
@ -284,27 +284,29 @@ pp.parseSubscripts = function (base, startPos, startLoc, noCalls) {
      node.object = base;
      node.callee = this.parseNoCallExpr();
      return this.parseSubscripts(this.finishNode(node, "BindExpression"), startPos, startLoc, noCalls);
-   } else if (this.eat(tt.questionDot)) {
-       let node = this.startNodeAt(startPos, startLoc);
-       node.object = base;
-       node.property = this.parseIdentifier(true);
-       node.computed = false;
-       node.nullPropagation = true;
-       base = this.finishNode(node, "MemberExpression");
+    } else if (this.eat(tt.questionDot)) {
+      base.nullPropagation = true;
+      if (this.eat(tt.bracketL)) {
+        const node = this.startNodeAt(startPos, startLoc);
+        node.object = base;
+        node.property = this.parseExpression();
+        node.computed = true;
+        this.expect(tt.bracketR);
+        base = this.finishNode(node, "MemberExpression");
+      }
+      else {
+        const node = this.startNodeAt(startPos, startLoc);
+        node.object = base;
+        node.property = this.parseIdentifier(true);
+        node.computed = false;
+        base = this.finishNode(node, "MemberExpression");
+      }
    } else if (this.eat(tt.dot)) {
      const node = this.startNodeAt(startPos, startLoc);
      node.object = base;
      node.property = this.parseIdentifier(true);
      node.computed = false;
-      node.nullPropagation = false;
      base = this.finishNode(node, "MemberExpression");
-    } else if (this.eat(tt.questionBracketL)) {
-       let node = this.startNodeAt(startPos, startLoc);
-       node.object = base;
-       node.property = this.parseExpression();
-       node.computed = true;
-       node.nullPropagation = true;
-       this.expect(tt.bracketR);
    } else if (this.eat(tt.bracketL)) {
      const node = this.startNodeAt(startPos, startLoc);
      node.object = base;
--- a/src/tokenizer/index.js
+++ b/src/tokenizer/index.js
@ -392,20 +392,16 @@ export default class Tokenizer {
  }

  readToken_question() { // '?'
-     let next = this.input.charCodeAt(this.state.pos + 1);
-     if(next === 46){ // 46 = question '.'
-       this.state.pos += 2;
-       return this.finishToken(tt.questionDot);
-     }
-     else if(next === 91){ // 91 = question '['
-       this.state.pos += 2;
-       return this.finishToken(tt.questionBracketL);
-     } 
-     else {
-       ++this.state.pos;
-       return this.finishToken(tt.question);
-     }
-   }
+    const next = this.input.charCodeAt(this.state.pos + 1);
+    if (next === 46) { // 46 = question '.'
+      this.state.pos += 2;
+      return this.finishToken(tt.questionDot);
+    }
+    else {
+      ++this.state.pos;
+      return this.finishToken(tt.question);
+    }
+  }

  getTokenFromCode(code) {
    switch (code) {
@ -825,7 +821,7 @@ export default class Tokenizer {
    const type = this.state.type;
    let update;

-    if (type.keyword && prevType === tt.dot) {
+    if (type.keyword && (prevType === tt.dot || prevType === tt.questionDot)) {
      this.state.exprAllowed = false;
    } else if (update = type.updateContext) {
      update.call(this, prevType);
--- a/src/tokenizer/types.js
+++ b/src/tokenizer/types.js
@ -75,8 +75,7 @@ export const types = {
  doubleColon: new TokenType("::", { beforeExpr }),
  dot: new TokenType("."),
  question: new TokenType("?", { beforeExpr }),
-  questionBracketL: new TokenType("?[", { beforeExpr, startsExpr }),
-  questionBracketL: new TokenType("?."),
+  questionDot: new TokenType("?."),
  arrow: new TokenType("=>", { beforeExpr }),
  template: new TokenType("template"),
  ellipsis: new TokenType("...", { beforeExpr }),
--- a/test/fixtures/experimental/uncategorised/63/actual.js
+++ b/test/fixtures/experimental/uncategorised/63/actual.js
@ -2,4 +2,4 @@ o?.x?.y

 o?.x ? o.x.z?.w : o.y?.z?.w

-o?[0]?[1]?.x
+o?.[0]?.["1"]?.x
--- a/test/fixtures/experimental/uncategorised/63/expected.json
+++ b/test/fixtures/experimental/uncategorised/63/expected.json
@ -1,7 +1,7 @@
 {
  "type": "File",
  "start": 0,
-  "end": 50,
+  "end": 54,
  "loc": {
    "start": {
      "line": 1,
@ -9,13 +9,13 @@
    },
    "end": {
      "line": 5,
-      "column": 12
+      "column": 16
    }
  },
  "program": {
    "type": "Program",
    "start": 0,
-    "end": 50,
+    "end": 54,
    "loc": {
      "start": {
        "line": 1,
@ -23,7 +23,7 @@
      },
      "end": {
        "line": 5,
-        "column": 12
+        "column": 16
      }
    },
    "sourceType": "script",
@ -85,7 +85,7 @@
                }
              },
              "name": "o",
-              "existentialOperator": true
+              "nullPropagation": true
            },
            "property": {
              "type": "Identifier",
@ -104,7 +104,7 @@
              "name": "x"
            },
            "computed": false,
-            "existentialOperator": true
+            "nullPropagation": true
          },
          "property": {
            "type": "Identifier",
@ -182,7 +182,7 @@
                }
              },
              "name": "o",
-              "existentialOperator": true
+              "nullPropagation": true
            },
            "property": {
              "type": "Identifier",
@ -295,7 +295,7 @@
                "name": "z"
              },
              "computed": false,
-              "existentialOperator": true
+              "nullPropagation": true
            },
            "property": {
              "type": "Identifier",
@ -390,7 +390,7 @@
                  "name": "y"
                },
                "computed": false,
-                "existentialOperator": true
+                "nullPropagation": true
              },
              "property": {
                "type": "Identifier",
@ -409,7 +409,7 @@
                "name": "z"
              },
              "computed": false,
-              "existentialOperator": true
+              "nullPropagation": true
            },
            "property": {
              "type": "Identifier",
@ -434,7 +434,7 @@
      {
        "type": "ExpressionStatement",
        "start": 38,
-        "end": 50,
+        "end": 54,
        "loc": {
          "start": {
            "line": 5,
@ -442,13 +442,13 @@
          },
          "end": {
            "line": 5,
-            "column": 12
+            "column": 16
          }
        },
        "expression": {
          "type": "MemberExpression",
          "start": 38,
-          "end": 50,
+          "end": 54,
          "loc": {
            "start": {
              "line": 5,
@ -456,13 +456,13 @@
            },
            "end": {
              "line": 5,
-              "column": 12
+              "column": 16
            }
          },
          "object": {
            "type": "MemberExpression",
            "start": 38,
-            "end": 47,
+            "end": 51,
            "loc": {
              "start": {
                "line": 5,
@ -470,13 +470,13 @@
              },
              "end": {
                "line": 5,
-                "column": 9
+                "column": 13
              }
            },
            "object": {
              "type": "MemberExpression",
              "start": 38,
-              "end": 43,
+              "end": 44,
              "loc": {
                "start": {
                  "line": 5,
@ -484,7 +484,7 @@
                },
                "end": {
                  "line": 5,
-                  "column": 5
+                  "column": 6
                }
              },
              "object": {
@ -502,62 +502,58 @@
                  }
                },
                "name": "o",
-                "existentialOperator": true
+                "nullPropagation": true
              },
              "property": {
-                "type": "Literal",
-                "start": 41,
-                "end": 42,
+                "type": "NumericLiteral",
+                "start": 42,
+                "end": 43,
                "loc": {
                  "start": {
                    "line": 5,
-                    "column": 3
+                    "column": 4
                  },
                  "end": {
                    "line": 5,
-                    "column": 4
+                    "column": 5
                  }
                },
-                "value": 0,
-                "rawValue": 0,
-                "raw": "0"
+                "value": 0
              },
              "computed": true,
-              "existentialOperator": true
+              "nullPropagation": true
            },
            "property": {
-              "type": "Literal",
-              "start": 45,
-              "end": 46,
+              "type": "StringLiteral",
+              "start": 47,
+              "end": 50,
              "loc": {
                "start": {
                  "line": 5,
-                  "column": 7
+                  "column": 9
                },
                "end": {
                  "line": 5,
-                  "column": 8
+                  "column": 12
                }
              },
-              "value": 1,
-              "rawValue": 1,
-              "raw": "1"
+              "value": "1"
            },
            "computed": true,
-            "existentialOperator": true
+            "nullPropagation": true
          },
          "property": {
            "type": "Identifier",
-            "start": 49,
-            "end": 50,
+            "start": 53,
+            "end": 54,
            "loc": {
              "start": {
                "line": 5,
-                "column": 11
+                "column": 15
              },
              "end": {
                "line": 5,
-                "column": 12
+                "column": 16
              }
            },
            "name": "x"