Merge branch 'master' of github.com:babel/babel

src/acorn/src/expression.js

@@ -226,7 +226,7 @@ pp.parseSubscripts = function(base, start, noCalls) {
   } else if (!noCalls && this.eat(tt.parenL)) {
     let node = this.startNodeAt(start)
     node.callee = base
-    node.arguments = this.parseExprList(tt.parenR, false)
+    node.arguments = this.parseExprList(tt.parenR, this.options.features["es7.trailingFunctionCommas"])
     return this.parseSubscripts(this.finishNode(node, "CallExpression"), start, noCalls)
   } else if (this.type === tt.backQuote) {
     let node = this.startNodeAt(start)

src/acorn/src/statement.js

@@ -458,7 +458,7 @@ pp.parseFunction = function(node, isStatement, allowExpressionBody, isAsync) {
 
 pp.parseFunctionParams = function(node) {
   this.expect(tt.parenL)
-  node.params = this.parseBindingList(tt.parenR, false, false)
+  node.params = this.parseBindingList(tt.parenR, false, this.options.features["es7.trailingFunctionCommas"])
 }
 
 // Parse a class declaration or literal (depending on the

src/babel/transformation/transformers/es7/trailing-function-commas.js

@@ -0,0 +1,7 @@
+export var metadata = {
+  stage: 1
+};
+
+export function check() {
+  return false;
+}

src/babel/transformation/transformers/index.js

@@ -1,5 +1,6 @@
 export default {
   "es7.classProperties":                   require("./es7/class-properties"),
+  "es7.trailingFunctionCommas":            require("./es7/trailing-function-commas"),
   "es7.asyncFunctions":                    require("./es7/async-functions"),
   "es7.decorators":                        require("./es7/decorators"),
 

test/acorn/tests-babel.js

@@ -3000,3 +3000,99 @@ test('export * as foo from "bar";', {
   sourceType: "module",
   features: { "es7.exportExtensions": true }
 });
+
+// ES7: Trailing Function Commas
+
+test("log(n, '=', 2,);", {
+  type: "Program",
+  start: 0,
+  end: 16,
+  body: [{
+    type: "ExpressionStatement",
+    start: 0,
+    end: 16,
+    expression: {
+      type: "CallExpression",
+      callee: {
+        type: "Identifier",
+        name: "log",
+        start: 0,
+        end: 3
+      },
+      arguments: [{
+        type: "Identifier",
+        name: "n",
+        start: 4,
+        end: 5
+      }, {
+        type: "Literal",
+        value: "=",
+        raw: "'='",
+        start: 7,
+        end: 10
+      }, {
+        type: "Literal",
+        raw: "2",
+        value: 2,
+        start: 12,
+        end: 13
+      }]
+    }
+  }]
+}, {
+  ecmaVersion: 7,
+  features: { "es7.trailingFunctionCommas": true }
+});
+
+test("function log(n, op, val,) { }", {
+  type: "Program",
+  start: 0,
+  end: 29,
+  body: [{
+    type: "FunctionDeclaration",
+    id: {
+      type: "Identifier",
+      name: "log",
+      start: 9,
+      end: 12
+    },
+    start: 0,
+    end: 29,
+    expression: false,
+    params: [{
+      type: "Identifier",
+      name: "n",
+      start: 13,
+      end: 14
+    }, {
+      type: "Identifier",
+      name: "op",
+      start: 16,
+      end: 18
+    }, {
+      type: "Identifier",
+      name: "val",
+      start: 20,
+      end: 23
+    }],
+    body: {
+      type: "BlockStatement",
+      start: 26,
+      end: 29,
+      body: []
+    }
+  }]
+}, {
+  ecmaVersion: 7,
+  features: { "es7.trailingFunctionCommas": true }
+});
+
+testFail("log(,);", "Unexpected token (1:4)", {
+  ecmaVersion: 7,
+  features: { "es7.trailingFunctionCommas": true }
+});
+
+testFail("function log(,) { }", "Unexpected token (1:13)", {
+  ecmaVersion: 7,
+  features: { "es7.trailingFunctionCommas": true }
+});

test/core/fixtures/transformation/es7.trailing-function-commas/call/actual.js

@@ -0,0 +1,4 @@
+Math.max(1,
+         2,
+         3,
+);

test/core/fixtures/transformation/es7.trailing-function-commas/call/expected.js

@@ -0,0 +1,3 @@
+"use strict";
+
+Math.max(1, 2, 3);

test/core/fixtures/transformation/es7.trailing-function-commas/declaration/actual.js

@@ -0,0 +1,8 @@
+function thisIsAFunctionWithAVeryLongNameAndWayTooManyParameters(
+  thisIsTheFirstParameter, andThisOneIsRelatedToIt,
+  butNotThisOne,
+  andNeitherThis,
+  inFactThereArentThatManyParameters,
+) {
+  throw null;
+}

test/core/fixtures/transformation/es7.trailing-function-commas/declaration/expected.js

@@ -0,0 +1,5 @@
+"use strict";
+
+function thisIsAFunctionWithAVeryLongNameAndWayTooManyParameters(thisIsTheFirstParameter, andThisOneIsRelatedToIt, butNotThisOne, andNeitherThis, inFactThereArentThatManyParameters) {
+  throw null;
+}

test/core/fixtures/transformation/es7.trailing-function-commas/options.json

@@ -0,0 +1,3 @@
+{
+  "optional": ["es7.trailingFunctionCommas"]
+}