node.JS路径解析之PATH模块使用方法详解

路径组成

path.dirname(p)

返回路径p所在的目录

var path = require('path');

console.log(path.dirname('/foo/bar/baz/asdf/a.txt')); // /foo/bar/baz/asdf

console.log(path.dirname('/foo/bar/baz/asdf/')); // /foo/bar/baz

console.log(path.dirname('c:/test/aaa')); // c:/test

path.basename(p[, ext])

返回路径的最后一个部分，即文件名。参数ext为需要截掉的后缀内容　

var path = require('path');

console.log(path.basename('/foo/bar/baz/asdf/a.txt')); // a.txt

console.log(path.basename('/foo/bar/baz/asdf/a.txt','.txt')); // a

console.log(path.basename('/foo/bar/baz/asdf/')); // asdf

console.log(path.basename('c:/test/aaa')); // aaa

path.extname(p)

返回路径p的扩展名，从最后一个'.'到字符串的末尾。如果最后一个部分没有'.'，或者路径是以'.'开头，则返回空字符串

var path = require('path');

console.log(path.extname('/foo/bar/baz/asdf/a.txt')); // .txt

console.log(path.extname('/foo/bar/baz/asdf/a.txt.b')); // .b

console.log(path.extname('/foo/bar/baz/asdf/a.')); // .

console.log(path.extname('c:/test/aaa/.')); // ''

console.log(path.extname('c:/test/aaa')); // ''

分隔符

path.sep

返回对应平台下的文件分隔符，win下为'\'，*nix下为'/'

var path = require('path');

console.log(path.sep); // win下为\，*nix下为/

console.log('foo\\bar\\baz'.split(path.sep)); // [ 'foo', 'bar', 'baz' ]

console.log('foo/bar/baz'.split(path.sep)); // win下返回['foo/bar/baz']，但在*nix系统下会返回['foo','bar','baz']

path.delimiter

返回对应平台下的路径分隔符，win下为';'，*nix下为':'

var path = require('path');

console.log(path.delimiter); //win下为“;”，*nix下为“:”

console.log(path.sep); // win下为\，*nix下为/

规范化

path.normalize(p)

规范化路径，处理冗余的“..”、“.”、“/”字符。发现多个斜杠时，会替换成一个斜杠。当路径末尾包含一个斜杠时，保留。windows系统使用反斜杠　

var path = require('path');

console.log(path.normalize('a/b/c/../user/bin'));//a\b\user\bin

console.log(path.normalize('a/b/c///../user/bin/'));//a\b\user\bin\

console.log(path.normalize('a/b/c/../../user/bin'));//a\user\bin

console.log(path.normalize('a/b/c/.././///../user/bin/..'));//a\user

console.log(path.normalize('a/b/c/../../user/bin/../../'));//a\

console.log(path.normalize('a/../../user/bin/../../'));//..\

console.log(path.normalize('a/../../user/bin/../../../../'));//..\..\..\

console.log(path.normalize('./a/.././user/bin/./'));//user\bin\

path.join([path1], [path2], [...])

将多个路径结合在一起，并转换为规范化路径　

var path = require('path');

console.log(path.join('////./a', 'b////c', 'user/'));//\a\b\c\user

console.log(path.join('a', '../../', 'user/'));//..\user\

绝对和相对

path.resolve([from ...], to)

从源地址 from 到目的地址 to 的绝对路径，类似在shell里执行一系列的cd命令

path.resolve('foo/bar', '/tmp/file/', '..', 'a/../subfile')

类似于:

cd foo/bar

cd /tmp/file/

cd ..

cd a/../subfile

pwd

[注意]如果某个from或to参数是绝对路径（比如 'e:/abc'，或是以“/”开头的路径），则将忽略之前的from参数

var path = require('path');

console.log(path.resolve('.', 'testfiles/..', 'trdlayer'));//d:\project\trdlayer

console.log(path.resolve('..', 'testfiles', 'a.txt'));//d:\testfiles\a.txt

console.log(path.resolve('d:', 'abc', 'd:/a'));//d:\a

console.log(path.resolve('abc', 'ok.gif'));//d:\project\abc\ok.gif

console.log(path.resolve('abc', '..', 'a/../subfile')); //d:\project\subfile

path.isabsolute(path)

path是一个绝对路径(比如 'e:/abc')，或者是以“/”开头的路径，二者都会返回true

var path = require('path');

console.log(path.isabsolute('../testfiles/seclayer'));//false

console.log(path.isabsolute('./join.js'));//false

console.log(path.isabsolute('temp'));//false

console.log(path.isabsolute('/temp/../..'));//true

console.log(path.isabsolute('e:/github/nodeapi/abc/efg'));//true

console.log(path.isabsolute('///temp123'));//true

path.relative(from, to)

获取从 from 到 to 的相对路径，可以看作 path.resolve 的相反实现

path.resolve(from, path.relative(from, to)) == path.resolve(to)

var path = require('path');

console.log(path.relative('c:\\\test', 'c:\\\impl\\bbb'));//..\impl\bbb

console.log(path.relative('c:/test/aaa', 'c:/bbb'));//..\..\bbb