Node.js path模块,获取文件后缀名操作

//path模块
var path=require('path'); /nodejs自带的模块/
var extname=path.extname("123.html"); //获取文件的后缀名 
console.log(extname);

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); 

let myPath = path.resolve(__dirname,'/img/so');
let myPath2 = path.resolve(__dirname,'./img/so');
let myPath3=path.resolve('/foo/bar', './baz');
let myPath4=path.resolve('/foo/bar', '/tmp/file/');
 
console.log(__dirname);      
console.log(myPath);  
console.log(myPath2);  
console.log(myPath3); 
console.log(myPath4);