RegExp() should not throw. Fixes #350.

paulmillr · Jun 17, 2015 · e7a8904 · e7a8904
1 parent 7b27b38
commit e7a8904
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/es6-shim.js b/es6-shim.js
@@ -1380,7 +1380,9 @@
     var OrigRegExp = RegExp;
     var RegExpShim = function RegExp(pattern, flags) {
       var calledWithNew = this instanceof RegExp;
-      if (!calledWithNew && (Type.regex(pattern) || pattern.constructor === RegExp)) {
+      if (!calledWithNew && arguments.length === 0) {
+        return new RegExp();
+      } else if (!calledWithNew && (Type.regex(pattern) || pattern.constructor === RegExp)) {
         return pattern;
       }
       if (Type.regex(pattern) && Type.string(flags)) {

diff --git a/test/regexp.js b/test/regexp.js
@@ -17,6 +17,12 @@ describe('RegExp', function () {
     expect(exported.RegExp).to.equal(RegExp);
   });
 
+  it('can be called with no arguments', function () {
+    var regex = RegExp();
+    expect(String(regex)).to.equal(String(RegExp.prototype));
+    expect(regex).to.be.an.instanceOf(RegExp);
+  });
+
   describe('constructor', function () {
     it('allows a regex as the pattern', function () {
       var a = /a/g;