path.join

参考来源：https://blog.csdn.net/qq_33745501/article/details/80270708

与path.resolve有点相似

参数无个数限制，从左至右将参数拼接成一个路径，支持..向上跳转,若有错误则报错

例如以下

const path = require('path');

let myPath = path.join(__dirname,'/img/so');

let myPath2 = path.join(__dirname,'./img/so');

let myPath3=path.join('/foo', 'bar', 'baz/asdf', 'quux', '..');

console.log(__dirname);         

console.log(myPath);   

console.log(myPath2); 

console.log(myPath3);