一、path模块的引入。

直接引用。node中自带的模块

const path = require('path');

二、path.join(path1，path2，path3.......)

作用：将路径片段使用特定的分隔符（window：\）连接起来形成路径，并规范化生成的路径。若任意一个路径片段类型错误，会报错。

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);

三、path.resolve([from...],to)

作用：把一个路径或路径片段的序列解析为一个绝对路径。相当于执行cd操作。

/被解析为根目录。

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);

输入

const path0 = path.resolve(ROOT_PATH, 'docs');
 const path1 = path.resolve(ROOT_PATH, '/docs');
 const path2 = path.resolve(ROOT_PATH, './docs');
 
 const path3 = path.join(ROOT_PATH, './docs');
 const path4 = path.join(ROOT_PATH, '/docs');
 const path5 = path.join(ROOT_PATH, 'docs');

 console.log(path0);
 console.log(path1);
 console.log(path2);
 console.log(path3);
 console.log(path4);
 console.log(path5);

输出

G:\编程测试练习\11-18\docs
G:\docs
G:\编程测试练习\11-18\docs
G:\编程测试练习\11-18\docs
G:\编程测试练习\11-18\docs
G:\编程测试练习\11-18\docs

总结

• path.resolve 中 'doc' 和 './doc' 等价。
• path.join 中 'doc' 、'/doc' 和 './doc' 三者等价。