[New] Detect and patch RegExp#toString in IE 8, which returns flags…

… in the wrong order. Closes es-shims#364.
Xotic750 · Dec 9, 2015 · a827b75 · a827b75
1 parent 9ae8165
commit a827b75
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Showing 3 changed files with 30 additions and 11 deletions.
diff --git a/.eslintrc b/.eslintrc
@@ -14,7 +14,7 @@
 		"max-statements": [1, 30],
 		"new-cap": [2, { "capIsNewExceptions": ["ToInteger", "ToObject", "ToPrimitive", "ToUint32"] }],
 		"no-constant-condition": [1],
-		"no-extend-native": [2, {"exceptions": ["Date", "Error"]}],
+		"no-extend-native": [2, {"exceptions": ["Date", "Error", "RegExp"]}],
 		"no-extra-parens": [0],
 		"no-extra-semi": [1],
 		"no-func-assign": [1],

diff --git a/es5-shim.js b/es5-shim.js
@@ -1768,4 +1768,22 @@ if (supportsDescriptors) {
     ensureNonEnumerable(Error.prototype, 'name');
 }
 
+if (String(/a/mig) !== '/a/gim') {
+    var regexToString = function toString() {
+        var str = '/' + this.source + '/';
+        if (this.global) {
+            str += 'g';
+        }
+        if (this.ignoreCase) {
+            str += 'i';
+        }
+        if (this.multiline) {
+            str += 'm';
+        }
+        return str;
+    };
+    // can't use defineProperties here because of toString enumeration issue in IE <= 8
+    RegExp.prototype.toString = regexToString;
+}
+
 }));
diff --git a/tests/spec/s-regexp.js b/tests/spec/s-regexp.js
@@ -6,20 +6,21 @@ describe('RegExp', function () {
     describe('#toString()', function () {
         describe('literals', function () {
           it('should return correct flags and in correct order', function () {
-              expect(/pattern/.toString()).toBe('/pattern/');
-              expect(/pattern/i.toString()).toBe('/pattern/i');
-              expect(/pattern/mi.toString()).toBe('/pattern/im');
-              expect(/pattern/im.toString()).toBe('/pattern/im');
-              expect(/pattern/mgi.toString()).toBe('/pattern/gim');
+              expect(String(/pattern/)).toBe('/pattern/');
+              expect(String(/pattern/i)).toBe('/pattern/i');
+              expect(String(/pattern/mi)).toBe('/pattern/im');
+              expect(String(/pattern/im)).toBe('/pattern/im');
+              expect(String(/pattern/mgi)).toBe('/pattern/gim');
           });
         });
+
         describe('objects', function () {
           it('should return correct flags and in correct order', function () {
-              expect(new RegExp('pattern').toString()).toBe('/pattern/');
-              expect(new RegExp('pattern', 'i').toString()).toBe('/pattern/i');
-              expect(new RegExp('pattern', 'mi').toString()).toBe('/pattern/im');
-              expect(new RegExp('pattern', 'im').toString()).toBe('/pattern/im');
-              expect(new RegExp('pattern', 'mgi').toString()).toBe('/pattern/gim');
+              expect(String(new RegExp('pattern'))).toBe('/pattern/');
+              expect(String(new RegExp('pattern', 'i'))).toBe('/pattern/i');
+              expect(String(new RegExp('pattern', 'mi'))).toBe('/pattern/im');
+              expect(String(new RegExp('pattern', 'im'))).toBe('/pattern/im');
+              expect(String(new RegExp('pattern', 'mgi'))).toBe('/pattern/gim');
           });
         });
     });