格式错了，最外面得是花括号:

{
    '炒菜': [ { dishName: '鱼香肉丝', price: 25, intro: 'test', index: 1, category: '炒菜', _id: 57666d75c8f2cb97bb07e50b, dishPic: 'http://localhost:8080/resources/5766671c1002808fbbd09ebd/dishes/57666d75c8f2cb97bb07e50b.jpg', comment: [], tags: [Object] }, { dishName: '宫保板筋', price: 23, intro: '', index: 0, category: '炒菜', _id: 57666d75c8f2cb97bb07e50a, dishPic: 'http://localhost:8080/resources/5766671c1002808fbbd09ebd/dishes/57666d75c8f2cb97bb07e50a.jpg', comment: [], tags: [Object] } ], '火锅': [ { dishName: '海底捞', price: 250, intro: 'test', index: 3, category: '火锅', _id: 57666d75c8f2cb97bb07e50d, dishPic: 'http://localhost:8080/resources/5766671c1002808fbbd09ebd/dishes/57666d75c8f2cb97bb07e50d.jpg', comment: [], tags: [Object] }, { dishName: '黑豆花肉圆子火锅', price: 80, intro: 'test', index: 2, category: '火锅', _id: 57666d75c8f2cb97bb07e50c, dishPic: 'http://localhost:8080/resources/5766671c1002808fbbd09ebd/dishes/57666d75c8f2cb97bb07e50c.jpg', comment: [], tags: [Object] } ], '燃烧': [ { dishName: '凌波', price: 123, intro: 'test', index: 4, category: '燃烧', _id: 57666d75c8f2cb97bb07e50e, dishPic: 'http://localhost:8080/resources/5766671c1002808fbbd09ebd/dishes/57666d75c8f2cb97bb07e50e.jpg', comment: [], tags: [Object] } ]
}