nodeJS之路径PATH模块

Posted 2020-09-20 小火柴的蓝色理想

[1]路径组成 [2]分隔符 [3]规范化 [4]绝对和相对

前面的话

　　path模块包含一系列处理和转换文件路径的工具集，通过 require(\'path\') 可用来访问这个模块。本文将详细介绍path模块

 

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