1. Read files
fs.readFile(path[,options],callback)
- Path File path to be read
- Options The default value of the optional parameter is null
- Callback callback function
- Err: error object
- Data: indicates a specific value
const fs=require('fs')
fs.readFile('./files/1.txt'.'utf8'.(err,data) = >{
if(err) return console.log(err.message)
console.log(data)
// Display conversion
//console.log(data.toString())
// Implicit conversion
//console.log(data+'')
})
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2. Write files
fs.writeFile(file,data[,options],callback)
- File File path to be written
- Data Indicates the data to be written
- Options The default value is UTF8
- Callback callback function
- Err Error object
const fs=require('fs')
fs.writeFile('./files/2.txt'.'You're the best'.err= >{
if(err) return console.log(err.message)
console.log('Write succeeded')})Copy the code
3. Copy files
- Fs. Used by copyFile (SRC, dest, mode, the callback) v8.5.0 +
- SRC Indicates the path of the file to be copied
- Dest Output file path
- Mode This parameter is optional
- Callback callback function
- Err Error object
const fs = require('fs')
fs.copyFile('./files/1.txt'.'./files/1-copy.txt'.err= > {
if (err) return console.log(err.message)
console.log('Copy successful')})Copy the code
4. Path Path processing
const fs = require('fs')
const path = require('path')
console.log(__dirname)//D: qianfeng stage 3 teacher day01 code
// console.log(__filename)//D:\ thousand frontage \ third stage \ teacher \day01\code\04-path Path processing.js
// const abspath = __dirname + '/files/1.txt'
// You are advised to use path.join in the future
// const abspath = path.join(__dirname, './files/1.txt')
// fs.readFile(abspath, 'utf8', (err, data) => {
// if (err) return console.log(err.message)
// console.log(data)
// })
// Web relative path relative file
// Node relative path relative to running environment
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Job: After reading the data in TXT, change the format and then write it to another file
const fs = require('fs')
const path = require('path')
const querystring = require('querystring')
fs.readFile(path.join('./1.txt'), 'utf8'.(err, dataStr) = > {
if (err) return console.log(err.message)
console.log(dataStr);
let newArr = []
let arr = dataStr.trim().split('\n')
const obj = {}
// console.log(arr)
arr.forEach(item= > {
// console.log(JSON.parse('{"' + item.replace(/ /g, '\",\"').replace(/=/g, '\":\"') + '"}'))
// newArr.push(JSON.parse('{"' + item.replace(/ /g, '\",\"').replace(/=/g, '\":\"') + '"}'))
// console.log(querystring.parse(item, ' '))
newArr.push(querystring.parse(item, ' '))
})
obj.message = newArr
// argument 1 STR
// Callback can be set to null
// Parameter 3 sets the data format
// JSON.stringify
fs.writeFile(path.join(__dirname, './2.json'), JSON.stringify(obj, null.'\t'), err= > {
if (err) return console.log(err.message)
console.log('Data conversion successful')})})Copy the code