JsFile: remove all duplicate tokens in any order.

Author: mikesherov

lib/js-file.js

@@ -143,12 +143,14 @@ JsFile.prototype = {
         // in duplicate tokens on `export default function() {}`
         // (https://code.google.com/p/esprima/issues/detail?id=631)
         if (this.getDialect() === 'es6') {
-            var lastToken;
+            var tokenHash = {};
             this._tree.tokens = this._tree.tokens.filter(function(token, i) {
-                var prevToken = lastToken;
-                lastToken = token;
+                var hashKey = token.range[0] + '_' + token.range[1];
+                var isDuplicate = tokenHash[hashKey];
 
-                return !prevToken || prevToken.range[0] !== token.range[0] || prevToken.range[1] !== token.range[1];
+                tokenHash[hashKey] = true;
+
+                return !isDuplicate;
             });
         }
 

test/js-file.js

@@ -205,6 +205,15 @@ describe('modules/js-file', function() {
             createHarmonyJsFile('export default function() {}').iterateTokenByValue('(', spy);
             assert(spy.calledOnce);
         });
+
+        it('should not have duplicate tokens in es6 export default statements', function() {
+            var spy = sinon.spy();
+            createHarmonyJsFile('export default function init() {\n' +
+            '  window.addEventListener(\'fb-flo-reload\', function(ev) {\n' +
+            '  });\n' +
+            '}').iterateTokenByValue('(', spy);
+            assert(spy.calledThrice);
+        });
     });
 
     describe('getNodeByRange', function() {