Angular2异常:必须定义令牌

Question

应用程序/ boot.ts

import {bootstrap} from 'angular2/platform/browser';
import {AppComponent} from './app.component';
bootstrap(AppComponent);

应用程序/ app.component.ts

import {Component} from 'angular2/core';
@Component({
  selector: 'my-app',
  template: '{{title}}'
})
class AppComponent {
  title: "app"
}

错误:

EXCEPTION: Token must be defined!
STACKTRACE:BrowserDomAdapter.logError @ angular2.dev.js:23514
ExceptionHandler.call                 @ angular2.dev.js:1147
(anonymous function)                  @ angular2.dev.js:14801
NgZone._notifyOnError                 @ angular2.dev.js:5796
collection_1.StringMapWrapper.merge.onError @ angular2.dev.js:5700
run                                   @ angular2-polyfills.js:141
(anonymous function)                  @ angular2.dev.js:5719
NgZone.run                            @ angular2.dev.js:5681
ApplicationRef_.bootstrap             @ angular2.dev.js:14906
bootstrap                             @ angular2.dev.js:25054
execute                               @ boot.ts:4
u                                     @ system.src.js:4597
execute                               @ system.src.js:4597
y                                     @ system.src.js:4597
...

Answer 1

这是另一个多次困扰我的错误.我忘了(再次)导出我的根组件.它应该是:

export class AppComponent {

如果我花时间仔细查看堆栈跟踪(而不是搜索StackOverflow而不是找到我确切的问题),我会注意到它引用了我写的一个文件boot.ts:4.