refactor(reflection): improved error message

Author: vsavkin

modules/angular2/src/reflection/reflection_capabilities.dart

@@ -1,6 +1,7 @@
 library reflection.reflection_capabilities;
 
 import 'reflection.dart';
+import 'package:angular2/src/facade/lang.dart';
 import 'types.dart';
 import 'dart:mirrors';
 
@@ -45,7 +46,7 @@ class ReflectionCapabilities {
  create(name, [a1, a2, a3, a4, a5, a6, a7, a8, a9, a10]).reflectee;
  }
 
- throw "Factory cannot take more than 10 arguments";
+ throw "Cannot create a factory for '${stringify(type)}' because its constructor has more than 10 arguments";
  }
 
  List<List> parameters(typeOrFunc) {

modules/angular2/src/reflection/reflection_capabilities.ts

@@ -1,4 +1,4 @@
-import {Type, isPresent, global} from 'angular2/src/facade/lang';
+import {Type, isPresent, global, stringify} from 'angular2/src/facade/lang';
 import {List, ListWrapper} from 'angular2/src/facade/collection';
 import {GetterFn, SetterFn, MethodFn} from './types';
 
@@ -39,7 +39,8 @@ export class ReflectionCapabilities {
  };
  };
 
- throw new Error("Factory cannot take more than 10 arguments");
+ throw new Error(
+ `Cannot create a factory for '${stringify(t)}' because its constructor has more than 10 arguments`);
  }
 
  _zipTypesAndAnnotaions(paramTypes, paramAnnotations): List<List<any>> {

modules/angular2/test/core/compiler/reflection_capabilities_spec.js

@@ -31,6 +31,18 @@ export function main() {
  }
 
  describe('reflection capabilities', () => {
+ describe("factory", () => {
+ it("should create a factory for a type", () => {
+ var f = rc.factory(ClassWithField);
+ expect(f("value").field).toEqual("value");
+ });
+
+ it("should throw when a constructor has more than 10 args", () => {
+ expect(() => rc.factory(ClassWith11Fields)).toThrowError(
+ new RegExp(`has more than 10 arguments`));
+ });
+ });
+
  it('can read out class annotations through annotations key', () => {
  assertTestClassAnnotations(rc.annotations(TestClass));
  });
@@ -115,6 +127,17 @@ class TestClassTypesOnly {
  constructor(a: P1, b: P2) {}
 }
 
+class ClassWithField {
+ field;
+ constructor(field) {
+ this.field = field;
+ }
+}
+class ClassWith11Fields {
+ constructor(a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10) {
+ }
+}
+
 // Mocking the data stored in global.Reflect as if TS was compiling TestClass above.
 var mockDataForTestClassTypesOnly = {
  'annotations': null,