nodeJS之路徑PATH模塊

前面的話

path模塊包含一系列處理和轉換文件路徑的工具集，通過 require("path")可用來訪問這個模塊。本文將詳細介紹path模塊

【path.dirname(p)】

返迴路徑p所在的目錄

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])】

返迴路徑的最後一個部分，即文件名。參數ext為需要截掉的後綴內容

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)】

返迴路徑p的擴展名，從最後一個"."到字元串的末尾。如果最後一個部分沒有"."，或者路徑是以"."開頭，則返回空字元串

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】

返回對應平台下的文件分隔符，win下為""，*nix下為"/"

var path = require("path");
console.log(path.sep); // win下為，*nix下為/
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系統下會返回["foo","bar","baz"]

【path.delimiter】

返回對應平台下的路徑分隔符，win下為";"，*nix下為":"

var path = require("path");
console.log(path.delimiter); //win下為「;」，*nix下為「:」
console.log(path.sep); // win下為，*nix下為/

規範化

【path.normalize(p)】

規範化路徑，處理冗餘的「..」、「.」、「/」字元。發現多個斜杠時，會替換成一個斜杠。當路徑末尾包含一個斜杠時，保留。Windows系統使用反斜杠

var path = require("path");
console.log(path.normalize("a/b/c/../user/bin"));//auserin
console.log(path.normalize("a/b/c///../user/bin/"));//auserin
console.log(path.normalize("a/b/c/../../user/bin"));//auserin
console.log(path.normalize("a/b/c/.././///../user/bin/.."));//auser
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/./"));//userin

【path.join([path1], [path2], [...])】

將多個路徑結合在一起，並轉換為規範化路徑

var path = require("path");
console.log(path.join("////./a", "b////c", "user/"));//acuser
console.log(path.join("a", "../../", "user/"));//..user

絕對和相對

【path.resolve([from ...], to)】

從源地址 from 到目的地址 to 的絕對路徑，類似在shell里執行一系列的cd命令

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

類似於:

cd foo/bar
cd /tmp/file/
cd ..
cd a/../subfile
pwd

[注意]如果某個from或to參數是絕對路徑（比如 "E:/abc"，或是以「/」開頭的路徑），則將忽略之前的from參數

var path = require("path");
console.log(path.resolve(".", "testFiles/..", "trdLayer"));//D:project rdLayer
console.log(path.resolve("..", "testFiles", "a.txt"));//D: estFilesa.txt
console.log(path.resolve("D:", "abc", "D:/a"));//D:a
console.log(path.resolve("abc", "ok.gif"));//D:projectabcok.gif
console.log(path.resolve("abc", "..", "a/../subfile")); //D:projectsubfile

【path.isAbsolute(path)】

path是一個絕對路徑(比如 "E:/abc")，或者是以「/」開頭的路徑，二者都會返回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)】

獲取從 from 到 to 的相對路徑，可以看作 path.resolve 的相反實現

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

var path = require("path");
console.log(path.relative("C:\ est", "C:\impl\bbb"));//..implbb
console.log(path.relative("C:/test/aaa", "C:/bbb"));//....bb
console.log(path.relative("C:/test/aaa", "D:/bbb"));//D:bb

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