Merge pull request #50 from y8n/master

fix function proxy toString error

index.js

@@ -136,18 +136,24 @@
     // There is a bug in Safari 10.1 and `Proxy`ing it is not enough.
     var forSureUsePolyfill = !decodesPlusesCorrectly;
     var useProxy = (!forSureUsePolyfill && nativeURLSearchParams && !isSupportObjectConstructor && self.Proxy);
+    var propValue; 
+    if (useProxy) {
+        // Safari 10.0 doesn't support Proxy, so it won't extend URLSearchParams on safari 10.0
+        propValue = new Proxy(nativeURLSearchParams, {
+            construct: function (target, args) {
+                return new target((new URLSearchParamsPolyfill(args[0]).toString()));
+            }
+        })
+        // Chrome <=60 .toString() on a function proxy got error "Function.prototype.toString is not generic"
+        propValue.toString = Function.prototype.toString.bind(URLSearchParamsPolyfill);
+    } else {
+        propValue = URLSearchParamsPolyfill;
+    }
     /*
      * Apply polifill to global object and append other prototype into it
      */
     Object.defineProperty(self, 'URLSearchParams', {
-        value: (useProxy ?
-            // Safari 10.0 doesn't support Proxy, so it won't extend URLSearchParams on safari 10.0
-            new Proxy(nativeURLSearchParams, {
-                construct: function(target, args) {
-                    return new target((new URLSearchParamsPolyfill(args[0]).toString()));
-                }
-            }) :
-            URLSearchParamsPolyfill)
+        value: propValue
     });
 
     var USPProto = self.URLSearchParams.prototype;