npm install --save angular-in-memory-web-api

import { InMemoryDbservice } from "angular-in-memory-web-api";
import { Todo } from "./todo.model";

export class InMemoryTodoDbservice implements InMemoryDbservice{
    createdb(){
        let todos:Todo[]=[
            {id:‘c24743b1-942e-0527-4810-fa1175b92d90‘,desc:‘Hello world‘,completed:falsE},{id:‘c24743b1-942e-0527-4810-fa1175b92d91‘,desc:‘Hello‘,{id:‘c24743b1-942e-0527-4810-fa1175b92d92‘,{id:‘c24743b1-942e-0527-4810-fa1175b92d93‘,desc:‘ world‘,{id:‘c24743b1-942e-0527-4810-fa1175b92d94‘,{id:‘c24743b1-942e-0527-4810-fa1175b92d95‘,{id:‘c24743b1-942e-0527-4810-fa1175b92d96‘,];
        return {todos};
    }
}

import { Injectable } from ‘@angular/core‘;
import { Todo } from "./todo.model";
import { UUID } from "angular2-uuid";

import { http,Headers } from "@angular/http";
import ‘rxjs/add/operator/toPromise‘;

@Injectable()
export class Todoservice {

  //定义web api地址和headers
  private api_url=‘api/todos‘;
  private headers=new Headers({‘Content-Type‘:‘application/json‘});

  //post /todo
  addTodo(desc:string):Promise<Todo>{
    let todo={
      id:UUID.UUID(),desc:desc,completed:false
    };
    return this.http
              .post(this.api_url,JSON.Stringify(todo),{headers:this.headers})
              .toPromise()
              .then(res=>res.json().data as Todo)
              .catch(this.handleError);
              

  }

  //error处理
  private handleError(error:any):Promise<any>{
    console.log(‘an error occurred:‘,error);
    return Promise.reject(error.message||error);
  }

  todos:Todo[]=[];

  constructor(private http:http) { }

}