const path=require('path');
let str='/root/a/b/1.txt';
//console.log(path.dirname(str));
// -  /root/a/b
//console.log(path.extname(str));
//   .txt
//console.log(path.basename(str));
//  1.txt

//console.log(path.resolve('/root/a/b', '../c', 'build', '..', 'strict'));
// \root\a\c\strict
//console.log(path.resolve(__dirname, 'build'));
// 当前目录下的build  绝对路径