Node
Node.js® is an open-source, cross-platform JavaScript runtime environment, is a JavaScript runtime built on the V8 JavaScript engine .
Node中无法使用DOM和BOM等浏览器内置API
学习的官网文档链接:https://nodejs.org/docs/latest-v17.x/api/documentation.html
fs fs.readFile 1 2 3 4 5 6 import { readFile } from 'fs' readFile ('./example/ex1.json' , (err, data ) => { console .log (data) })
1 2 3 4 5 6 7 const fs = require ("fs" ) fs.readFile ("./example/ex1.json" , (err, data ) => { console .log (data) })
1 2 3 4 5 6 7 const fs = require ("fs" ) fs.readFile ("./example/ex1.json" , "utf8" , (err, data ) => { console .log (data) })
可以判断err对象是否为null,从而知晓文件读取的是否成功
fs.writeFile 1 2 3 4 fs.writeFile ("./example/ex1.json" , "123" ,'utf8' , (err ) => { console .log (err) })
example
使用fs,将源文件的数据整理放到另一个文件中
源文件:
1 小红=99 小白=100 小黄=80 小1=100
目标内容:
1 2 3 4 小红:99 小白:100 小黄:80 小1:100
实现:
1 2 3 4 5 6 7 8 const fs = require ("fs" ) fs.readFile ("./example/grade.txt" , "utf8" , (err, data ) => { let tem1 = data.replace (/\=/g , ":" ) let tem2 = tem1.replace (/\ /g , "\n" ) fs.writeFile ("./example/grade-1.txt" , tem2, (err ) => { console .log (err) }) })