Allow lexical declaration with const in a ForInStatement.

Refs jquery#1065
ariya · Feb 23, 2015 · 9a62208 · 9a62208
1 parent dae6e7d
commit 9a62208
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Showing 2 changed files with 59 additions and 2 deletions.
diff --git a/esprima.js b/esprima.js
@@ -3095,8 +3095,10 @@
         }
 
         if (kind === 'const') {
-            expect('=');
-            init = parseAssignmentExpression();
+            if (!matchKeyword('in')) {
+                expect('=');
+                init = parseAssignmentExpression();
+            }
         } else if (match('=')) {
             lex();
             init = parseAssignmentExpression();

diff --git a/test/test.js b/test/test.js
@@ -21024,6 +21024,61 @@ var testFixture = {
             }
         },
 
+        'for (const x in y){}': {
+            type: 'ForInStatement',
+            left: {
+                type: 'VariableDeclaration',
+                declarations: [{
+                    type: 'VariableDeclarator',
+                    id: {
+                        type: 'Identifier',
+                        name: 'x',
+                        range: [11, 12],
+                        loc: {
+                            start: { line: 1, column: 11 },
+                            end: { line: 1, column: 12 }
+                        }
+                    },
+                    init: null,
+                    range: [11, 12],
+                    loc: {
+                        start: { line: 1, column: 11 },
+                        end: { line: 1, column: 12 }
+                    }
+                }],
+                kind: 'const',
+                range: [5, 12],
+                loc: {
+                    start: { line: 1, column: 5 },
+                    end: { line: 1, column: 12 }
+                }
+            },
+            right: {
+                type: 'Identifier',
+                name: 'y',
+                range: [16, 17],
+                loc: {
+                    start: { line: 1, column: 16 },
+                    end: { line: 1, column: 17 }
+                }
+            },
+            body: {
+                type: 'BlockStatement',
+                body: [],
+                range: [18, 20],
+                loc: {
+                    start: { line: 1, column: 18 },
+                    end: { line: 1, column: 20 }
+                }
+            },
+            each: false,
+            range: [0, 20],
+            loc: {
+                start: { line: 1, column: 0 },
+                end: { line: 1, column: 20 }
+            }
+        },
+
         'for (var x = y = z in q);': {
             type: 'ForInStatement',
             left: {