Path模块中常用函数的使用是怎样的

官网地址:https://nodejs.org/api/path.html

path.resolve([...paths])#

功能：该函数将一个路径序列或路径片段组合成一个绝对路径；

path.resolve([path1][, path2][, ...]) 从右向左依次拼接该路径序列，直到构成一个绝对路径。例如，输入参数：/foo, /bar, baz, 调用函数path.resolve('/foo', '/bar', 'baz')后返回结果是 /bar/baz；

如果处理完所有参数仍然没有构成一个绝对路径，就使用当前工作目录的绝对路径；结果返回的路径是经normalized后的，尾随斜线是没有的，除非是根路径；

Zero-lengthpathsegments are ignored.

如果路径序列中没有可用的路径片段，该函数将返回当前工作目录的绝对路径；

例子：

path.resolve('/foo/bar', './baz')
// Return: '/foo/bar/baz' 

path.resolve('/foo/bar', '/tmp/file/')
// Return: '/tmp/file'

path.resolve('wwwroot', 'static_files/png/', '../gif/image.gif')
//如果当前工作目录是/home/myself/node,
//返回结果是: '/home/myself/node/wwwroot/static_files/gif/image.gif'

　　如果有任何参数不是字符串，将会抛出TypeError错误；

path.join([...paths])#

Thepath.join()method joins all givenpathsegments together using the platform specific separator as a delimiter, then normalizes the resulting path.

作用：该函数使用指定分隔符将参数中所有路径片段连接到一起，并返回normalize后的结果路径。

Zero-lengthpathsegments are ignored. If the joined path string is a zero-length string then'.'will be returned, representing the current working directory.

如果连接的参数长度为0字符串，将会返回'.' , 表示当前工作目录

例子:

1 path.join('/foo', 'bar', 'baz/asdf', 'quux', '..')
2 //Return: '/foo/bar/baz/asdf'
3 
4 path.join('foo', {}, 'bar')
5 //throws TypeError：Arguments to path.join must be strings

如果参数中有任何路径片段不是字符串，将会抛出TypeError错误；

path.normalize(path)#

Thepath.normalize()method normalizes the givenpath, resolving'..'and'.'segments.

作用：标准化路径，处理'..'和'.'

When multiple, sequential path segment separation characters are found (e.g./on POSIX and\on Windows), they are replaced by a single instance of the platform specific path segment separator. 后缀分隔符将保留；

If thepathis a zero-length string,'.'is returned, representing the current working directory.

如果path是长度为0的字符串，将会返回'.' , 表示当前工作目录

For example on POSIX:

1 path.normalize('/foo/bar//baz/asdf/quux/..') 
2 // Returns: '/foo/bar/baz/asdf' 

On Windows:

1 path.normalize('C:\\temp\\\\foo\\bar\\..\\')
2 //Returns: 'C:\\temp\\foo\\'

path.format(pathObject)#

Thepath.format()method returns a path string from an object. This is the opposite ofpath.parse().

When providing properties to thepathObjectremember that there are combinations where one property has priority over another:

For example, on POSIX:

 1 // If `dir`, `root` and `base` are provided,
 2 // `${dir}${path.sep}${base}`
 3 // will be returned. `root` is ignored.
 4 path.format({
 5   root: '/ignored',
 6   dir: '/home/user/dir',
 7   base: 'file.txt'
 8 });
 9 // Returns: '/home/user/dir/file.txt'
10 
11 // `root` will be used if `dir` is not specified.
12 // If only `root` is provided or `dir` is equal to `root` then the
13 // platform separator will not be included. `ext` will be ignored.
14 path.format({
15   root: '/',
16   base: 'file.txt',
17   ext: 'ignored'
18 });
19 // Returns: '/file.txt'
20 
21 // `name` + `ext` will be used if `base` is not specified.
22 path.format({
23   root: '/',
24   name: 'file',
25   ext: '.txt'
26 });
27 // Returns: '/file.txt'

On Windows:

1 path.format({
2   dir : "C:\\path\\dir",
3   base : "file.txt"
4 });
5 // Returns: 'C:\\path\\dir\\file.txt'