Angular 4依赖注入学习教程之简介（一）

npm install -g @angular/cli

ng new PROJECT-NAME

cd PROJECT-NAME
ng serve

export default class Body { }

export default class Doors { }

export default class Engine {
 start() {
 console.log('🚗开动鸟~~~');
 }
}

import Engine from './engine';
import Doors from './doors';
import Body from './body';

export default class Car {
 engine: Engine;
 doors: Doors;
 body: Body;

 constructor() {
 this.engine = new Engine();
 this.body = new Body();
 this.doors = new Doors();
 }

 run() {
 this.engine.start();
 }
}

let car = new Car(); // 造辆新车
car.run(); // 开车上路咯

export default class Car {
 engine: Engine;
 doors: Doors;
 body: Body;

 constructor(engine, body, doors) {
 this.engine = engine;
 this.body = body;
 this.doors = doors;
 }

 run() {
 this.engine.start();
 }
}

let engine = new NewEngine();
let body = new Body();
let doors = new Doors();
this.car = new Car(engine, body, doors);
this.car.run();

@Injectable()
export default class Car {
 constructor(
 private engine: Engine, 
 private body: Body, 
 private doors: Doors) {}
 
 run() {
 this.engine.start();
 }
};

import { ReflectiveInjector } from '@angular/core';

let injector = ReflectiveInjector.resolveAndCreate([Car, 
 Engine, Doors, Body]);
let car = injector.get(Car);
car.run();