以异步/等待方式编写方法

Question

这是一个书籍捐赠项目，我试图在 async/等待 Way中编写一些方法。

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;
    }
}

catalogfile：它如何结构

[
  {
    "_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：类这是我尝试调用方法

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)

我得到此错误 booksrepo未定义

我不知道问题在哪里

Answer 1

看起来您有出口/导入的问题。

首先，您必须在文件中导出类：

module.exports = BooksRepo;

然后在使用的文件中导入它：

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

或者：

export default class BooksRepo { ...

和

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