Question

这是一个图书捐赠项目，我正在尝试以 async / await 的方式编写一些方法。

BooksRepo：具有所有方法的类

class BooksRepo {
    constructor() {
        this.fse = require('fs-extra');
        this.catalogFilePath = '../data/catalog.books.json';
    }


    async readFileAsync(filePath) {
        let data = await this.fse.readFile(filePath);
        let parsedData = await JSON.parse(data);

        return parsedData;
    }



    async getBook(bookName) {
        let books = await this.readFileAsync(this.catalogFilePath);
        let book = books.find(b => b.title == bookName);
        return book;
    }

}

目录文件：结构示例

[
  {
    "_id": 1,
    "title": "Unlocking Android",
    "isbn": "1933988673",
    "pageCount": 416,
    "publishedDate": {
      "$date": "2009-04-01T00:00:00.000-0700"
    },
    "thumbnailUrl": "https://s3.amazonaws.com/AKIAJC5RLADLUMVRPFDQ.book-thumb-images/ableson.jpg",
    "shortDescription": "Unlocking Android: A Developer's Guide provides concise...",
    "longDescription": "Android is an open source mobile phone platform based on the Linux operating ...",
    "status": "PUBLISH",
    "authors": [
      "W. Frank Ableson",
      "Charlie Collins",
      "Robi Sen"
    ],
    "categories": [
      "Open Source",
      "Mobile"
    ]
  },

app：类，这就是我试图调用方法的方式

let booksRepo = new BooksRepo();
    booksRepo.readFileAsync(booksRepo.catalogFilePath).then(result=> console.log(result));

    let books = booksRepo.getBook("Android in Action, Second Edition");

    console.log(books)

我收到此错误 未定义BooksRepo

我不知道问题出在哪里

Answer 1

您似乎对进出口有问题。

首先，您必须将类导出到其所在的文件中：

module.exports = BooksRepo;

然后将其导入使用的文件中：

var BooksRepo = require('./books-repo');

或者：

export default class BooksRepo { ...

和

import BooksRepo from './books-repo.js';

以异步/等待方式编写方法

1 个答案: