fix angular#595, refactor ZoneAwareError property copy

lib/zone.ts

@@ -1330,38 +1330,66 @@ const Zone: ZoneType = (function(global: any) {
   let frameParserStrategy = null;
   const stackRewrite = 'stackRewrite';
 
-  const assignAll = function(to, from) {
-    if (!to) {
-      return to;
-    }
+  const createProperty = (key) => {
+    const name = __symbol__(key);
+    return {
+      configurable: true,
+      enumerable: true,
+      get: function() {
+        if (!this[name]) {
+          this[name] = this[__symbol__('error')][key];
+        }
+        return this[name];
+      },
+      set: function(value) {
+        this[name] = value;
+      }
+    };
+  };
 
-    if (from) {
-      let keys = Object.getOwnPropertyNames(from);
-      for (let i = 0; i < keys.length; i++) {
-        const key = keys[i];
-        // Avoid bugs when hasOwnProperty is shadowed
-        if (Object.prototype.hasOwnProperty.call(from, key)) {
-          to[key] = from[key];
+  const createMethodProperty = (key) => {
+    return {
+      configurable: true,
+      enumerable: true,
+      writable: true,
+      value: function() {
+        const error = this[__symbol__('error')];
+        let errorMethod = error[key] || this[key];
+        if (errorMethod) {
+          return errorMethod.apply(error, arguments);
         }
       }
+    };
+  };
 
-      // copy all properties from prototype
-      // in Error, property such as name/message is in Error's prototype
-      // but not enumerable, so we copy those properties through
-      // Error's prototype
-      const proto = Object.getPrototypeOf(from);
-      if (proto) {
-        let pKeys = Object.getOwnPropertyNames(proto);
-        for (let i = 0; i < pKeys.length; i++) {
-          const key = pKeys[i];
-          // skip constructor
-          if (key !== 'constructor') {
-            to[key] = from[key];
-          }
+  const createErrorProperties = () => {
+    const props = Object.create(null);
+    const error = new NativeError();
+    let keys = Object.getOwnPropertyNames(error);
+    for (let i = 0; i < keys.length; i++) {
+      const key = keys[i];
+      // Avoid bugs when hasOwnProperty is shadowed
+      if (Object.prototype.hasOwnProperty.call(error, key)) {
+        props[key] = createProperty(key);
+      }
+    }
+    const proto = NativeError.prototype;
+    if (proto) {
+      let pKeys = Object.getOwnPropertyNames(proto);
+      for (let i = 0; i < pKeys.length; i++) {
+        const key = pKeys[i];
+        // skip constructor
+        if (key !== 'constructor' && key !== 'toString' && key !== 'toSource') {
+          props[key] = createProperty(key);
         }
       }
     }
-    return to;
+
+    props['originalStack'] = createProperty('originalStack');
+    props['zoneAwareStack'] = createProperty('zoneAwareStack');
+    props['toString'] = createMethodProperty('toString');
+    props['toSource'] = createMethodProperty('toSource');
+    return props;
   };
 
   /**
@@ -1378,6 +1406,7 @@ const Zone: ZoneType = (function(global: any) {
     }
     // Create an Error.
     let error: Error = NativeError.apply(this, arguments);
+    this[__symbol__('error')] = error;
 
     // Save original stack trace
     error.originalStack = error.stack;
@@ -1414,11 +1443,12 @@ const Zone: ZoneType = (function(global: any) {
       }
       error.stack = error.zoneAwareStack = frames.join('\n');
     }
-    return assignAll(this, error);
+    return this;
   }
 
   // Copy the prototype so that instanceof operator works as expected
-  ZoneAwareError.prototype = NativeError.prototype;
+  ZoneAwareError.prototype = Object.create(NativeError.prototype,
+    createErrorProperties());
   ZoneAwareError[Zone.__symbol__('blacklistedStackFrames')] = blackListedStackFrames;
   ZoneAwareError[stackRewrite] = false;
 

test/common/Error.spec.ts

@@ -67,6 +67,46 @@ describe('ZoneAwareError', () => {
     }
   });
 
+  it('should not use child Error class get/set in ZoneAwareError constructor', () => {
+    // simulate @angular/facade/src/error.ts
+    class BaseError extends Error {
+      /** @internal **/
+      _nativeError: Error;
+
+      constructor(message: string) {
+        super(message);
+        const nativeError = new Error(message) as any as Error;
+        this._nativeError = nativeError;
+      }
+
+      get message() {
+        return this._nativeError.message;
+      }
+      set message(message) {
+        this._nativeError.message = message;
+      }
+      get name() {
+        return this._nativeError.name;
+      }
+      get stack() {
+        return (this._nativeError as any).stack;
+      }
+      set stack(value) {
+        (this._nativeError as any).stack = value;
+      }
+      toString() {
+        return this._nativeError.toString();
+      }
+    }
+
+    const func = () => {
+      const error = new BaseError('test');
+      expect(error.message).toEqual('test');
+    };
+
+    expect(func).not.toThrow();
+  });
+
   it('should show zone names in stack frames and remove extra frames', () => {
     const rootZone = getRootZone();
     const innerZone = rootZone.fork({name: 'InnerZone'});