Add support for ArrowFunctionExpression

ref #33

escope.js

@@ -1,6 +1,7 @@
 /*
-  Copyright (C) 2012-2013 Yusuke Suzuki <[email protected]>
+  Copyright (C) 2012-2014 Yusuke Suzuki <[email protected]>
   Copyright (C) 2013 Alex Seville <[email protected]>
+  Copyright (C) 2014 Thiago de Arruda <[email protected]>
 
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:
@@ -342,6 +343,11 @@
             return true;
         }
 
+        // ArrowFunctionExpression's scope is always strict scope.
+        if (block.type === Syntax.ArrowFunctionExpression) {
+            return true;
+        }
+
         if (scope.type === 'function') {
             body = block.body;
         } else if (scope.type === 'global') {
@@ -350,6 +356,7 @@
             return false;
         }
 
+        // Search 'use strict' directive.
         if (options.directive) {
             for (i = 0, iz = body.body.length; i < iz; ++i) {
                 stmt = body.body[i];
@@ -775,7 +782,10 @@
         if (this.attached) {
             return node[Scope.mangledName] || null;
         }
-        if (this.__isScopeRequired(node)) {
+
+        // It may return false result. (for example, if node is the FunctionBody, it may return true under ES6 mode.)
+        // But it will be filtered the subsequent exploring.
+        if (this.__isScopeRequired(node, null)) {
             for (i = 0, iz = this.scopes.length; i < iz; ++i) {
                 scope = this.scopes[i];
                 if (!scope.functionExpressionScope) {
@@ -828,7 +838,7 @@
 
     ScopeManager.prototype.__isScopeRequired = function (node, parent) {
         function isFunctionScopeRequired(node) {
-            return node.type === Syntax.FunctionExpression || node.type === Syntax.FunctionDeclaration;
+            return node.type === Syntax.FunctionExpression || node.type === Syntax.FunctionDeclaration || node.type === Syntax.ArrowFunctionExpression;
         }
 
         function isVariableScopeRequired(node) {
@@ -847,6 +857,9 @@
                 }
                 return true;
             }
+            if (node.type === Syntax.ArrowFunctionExpression) {
+                return true;
+            }
         }
         return isScopeRequired(node);
     };

test/es6-arrow-function-expression.coffee

@@ -0,0 +1,56 @@
+# -*- coding: utf-8 -*-
+#  Copyright (C) 2014 Yusuke Suzuki <[email protected]>
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in the
+#      documentation and/or other materials provided with the distribution.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+#  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+#  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+#  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+#  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+#  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+expect = require('chai').expect
+harmony = require '../third_party/esprima'
+escope = require '..'
+
+describe 'ES6 arrow function expression', ->
+    it 'materialize scope for arrow function expression', ->
+        ast = harmony.parse """
+        var arrow = () => {
+            let i = 0;
+            var j = 20;
+            console.log(i);
+        }
+        """
+
+        scopeManager = escope.analyze ast, ecmaVersion: 6
+        expect(scopeManager.scopes).to.have.length 2
+
+        scope = scopeManager.scopes[0]
+        expect(scope.type).to.be.equal 'global'
+        expect(scope.block.type).to.be.equal 'Program'
+        expect(scope.isStrict).to.be.false
+        expect(scope.variables).to.have.length 1
+
+        scope = scopeManager.scopes[1]
+        expect(scope.type).to.be.equal 'function'
+        expect(scope.block.type).to.be.equal 'ArrowFunctionExpression'
+        expect(scope.isStrict).to.be.true
+        expect(scope.variables).to.have.length 3
+        expect(scope.variables[0].name).to.be.equal 'arguments'
+        expect(scope.variables[1].name).to.be.equal 'i'
+        expect(scope.variables[2].name).to.be.equal 'j'
+
+# vim: set sw=4 ts=4 et tw=80 :

test/es6-block-scope.coffee

@@ -28,10 +28,10 @@ escope = require '..'
 describe 'ES6 block scope', ->
     it 'let is materialized in ES6 block scope#1', ->
         ast = harmony.parse """
-{
-    let i = 20;
-    i;
-}
+        {
+            let i = 20;
+            i;
+        }
         """
 
         scopeManager = escope.analyze ast, ecmaVersion: 6
@@ -51,11 +51,11 @@ describe 'ES6 block scope', ->
 
     it 'let is materialized in ES6 block scope#2', ->
         ast = harmony.parse """
-{
-    let i = 20;
-    var i = 20;
-    i;
-}
+        {
+            let i = 20;
+            var i = 20;
+            i;
+        }
         """
 
         scopeManager = escope.analyze ast, ecmaVersion: 6