SyntaxError：JSON.parse：JSON数据第1行第1列的意外字符 - AngularJS

Question

我很早就开始在Angular2中找到恼人的错误，在控制台中我遇到了这个错误

  

onError：SyntaxError：JSON.parse：JSON数据第1行第1列的意外字符

这是我的book.service.ts代码

import { Injectable } from 'angular2/core';
import { Book } from './book';
import {Http} from 'angular2/http';
import 'rxjs/add/operator/map';

@Injectable()
export class BookService{
    books:Array<Book>;

    constructor(private _http: Http) {

    }

    getBooks() {
        return this._http.get('/api/books')
            .map(res => res.json());
    }
}

我的app.component.ts

import {Component} from 'angular2/core';
import { BookService } from './book.service';
import { Book } from './book';
import {BooksFilterPipe} from './book.filter';
import {HTTP_PROVIDERS} from 'angular2/http';

@Component({
    selector: 'my-app',
    templateUrl: 'app/book.component.html',
    providers: [BookService, HTTP_PROVIDERS],
    pipes: [BooksFilterPipe]
})

export class AppComponent{
    books:Array<Book>;

    constructor(private _bookService: BookService) { }

    getBooks() {
        this._bookService
            .getBooks()
            .subscribe(
                books => this.books = books,
                error => console.log('onError: %s', error)
            );
    }

    ngOnInit() {
        this.getBooks();
    }
}

我的ApiController（路由很好）

<?php

namespace Books\Controller;

use Bootstrap\App;

class ApiController extends App{
    public function getBooksAction(){
        $em = $this->getEntityManager();

        $books = $em->getRepository('Books\Model\Books')->findAll();

        $newBooks = [];

        foreach ($books as $book) {
            $newBooks[] = $book->toArray();
        }

        return $this->renderAjax($newBooks);
    }
}

这是我的命令控制台日志

  

的console.log（this._bookService.getBooks（））;

screenshot from Firefox

帮我解决问题。