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使用ES6 promise封装文件读写操作 #5

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lensh opened this issue Jul 25, 2017 · 0 comments
Open

使用ES6 promise封装文件读写操作 #5

lensh opened this issue Jul 25, 2017 · 0 comments

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@lensh
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lensh commented Jul 25, 2017

使用ES6 promise封装文件读写操作

nodejs的 fs 文件系统操作都是异步的,充满了大量的回调函数,存在难以忍受的回调地狱。
现在我们可以使用ES6 promise封装,来解决这个问题。
具体代码如下:

//  fs-async.js文件

import fs from 'fs'

/**
 * [读文件]
 * @param  {[type]} filePath [文件路径]
 * @return {[type]}          [description]
 */
export const readFile = (filePath) => {
	return new Promise((reslove, reject) => {
		fs.readFile(filePath, 'utf8', (err, data) => {
			if (!err) {
				reslove(JSON.parse(data))
			} else {
				reject(err)
			}
		})
	})
}

/**
 * [写文件]
 * @param  {[type]} filePath [文件路径]
 * @param  {[type]} data     [新的文件数据]
 * @return {[type]}          [description]
 */
export const writeFile = (filePath, data) => {
	return new Promise((reslove, reject) => {
		fs.writeFile(filePath, JSON.stringify(data), (err) => {
			if (err) {
				reject(err)
			}
		})
	})
}

封装后我们可以使用 async/await以同步的方式来读取文件内容了。

import {readFile,writeFile} from './fs-async'
const getData=async()=>{
    const data=await readFile('./users.json')
   console.log(data)
}
getData()     //会打印出文件的内容
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