3 基本

一，fs
noded.js自带的模板，实现文件的读写
1-1 同步的读取

const fs = require("fs");
/* fs是node.js自带的模块 实现文件的读写 */
var res = fs.readFileSync("./a.json");
console.log(res.toString())

1-2 异步读取

fs.readFile("./a.json",(err,res)=>{
    if(err){
        throw new Error("读取错误")
    }else{
        console.log(res.toString())
    }
})

二、process进程

process.cwd() //获取当前文件所在的路径
process.env  //获取当前应用所在的环境
process.execPath  //可以获取执行文件所在的执行环境

1-1 basename

c:/data/logo.jpg
# logo.jpg
path.basename("c:/data/logo.jpg")

1-2 join-resolve

都是解决路径问题

const path = require("path");
var s = path.join(__dirname,"static");
console.log(s)
var t = path.resolve(__dirname,"static");
console.log(t)

1-3 extname 获取文件拓展名

console.log(path.extname(process.execPath))

四、读取静态资源

yarn add koa-static

const koa = require("koa");
const app = new koa();
const path = require("path");
const static = require("koa-static");
app.use(static(path.join(__dirname,"static")))
app.listen(8000);