javascript 如何检查路径是绝对路径还是相对路径
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How to check if a path is absolute or relative
提问by Manuel Di Iorio
UNIX absolute path starts with '/', whereas Windows starts with alphabet 'C:' or '\'. Does node.js has a standard multiplatform function to check if a path is absolute or relative ?
UNIX 绝对路径以“/”开头，而 Windows 以字母“C:”或“\”开头。node.js 是否具有标准的多平台功能来检查路径是绝对路径还是相对路径？
回答by chresse
Since node version 0.12.0 you can use the path.isAbsolute(path)function from the pathmodule.
从节点版本 0.12.0 开始，您可以使用path模块中的path.isAbsolute(path)功能。
i.e:
IE：
var path = require('path');
if(path.isAbsolute(myPath)) {
//...
}
回答by Denys Séguret
You could use
你可以用
path.resolve(yourPath)===yourPath
If your path isn't normalized, use
如果您的路径未标准化，请使用
path.resolve( yourPath ) == path.normalize( yourPath )
回答by peoro
As commented to dystroy's answer, the proposed solutions don't work if an absolute path is not already normalized (for example the path: ///a//..//b//./).
正如对dystroy的回答所评论的那样，如果绝对路径尚未标准化（例如路径：），则建议的解决方案不起作用///a//..//b//./。
A correct solution is:
正确的解决方法是：
path.resolve(yourPath) === path.normalize(yourPath)
As Marc Diethelmsuggests in the comments, this has still some issues, since path.resolveremoves trailing slashes while path.normalizedoesn't.
正如Marc Diethelm在评论中所建议的那样，这仍然存在一些问题，因为path.resolve删除了尾部斜杠而path.normalize没有删除。
I'm not sure how these function exactly behave (as you can read in the comments), anyway the following snippet seem to work fine at least in Linux environments:
我不确定这些函数的确切行为（正如您在评论中所读到的），无论如何，以下代码段至少在 Linux 环境中似乎可以正常工作：
path.resolve(yourPath) === path.normalize(yourPath).replace( RegExp(path.sep+'$'), '' );
回答by TomDotTom
This is a little convoluted, but the most robust way I've found using just the (pre node 0.12.0) path module
这有点令人费解，但我发现的最强大的方法是仅使用（节点前 0.12.0）路径模块
function isAbsolute(p) {
return path.normalize(p + '/') === path.normalize(path.resolve(p) + '/');
}
It should be noted that path.isAbsolute exists from node 0.12.0 onwards.
需要注意的是 path.isAbsolute 从节点 0.12.0 开始就存在了。
回答by Javier Ros
I have no idea about node.js, but you can see the source of path.js in github: https://github.com/joyent/node/blob/master/lib/path.js
我对node.js一无所知，但是你可以在github中看到path.js的源码：https: //github.com/joyent/node/blob/master/lib/path.js
You can see:
你可以看到：
// windows version
exports.isAbsolute = function(path) {
var result = splitDeviceRe.exec(path),
device = result[1] || '',
isUnc = device && device.charAt(1) !== ':';
// UNC paths are always absolute
return !!result[2] || isUnc;
};
And:
和：
// posix version
exports.isAbsolute = function(path) {
return path.charAt(0) === '/';
};
回答by Shadrack N. John
isRelative(url){
return (/^(\.){1,2}(\/){1,2}$/.test(url.slice(0,3)) ||
/(\/){1,2}(\.){1,2}(\/){1,2}/.test(url));
}
This makes it easy to check whether a path is relative despite of absence of node path module API.
尽管没有节点路径模块 API，这使得检查路径是否是相对的很容易。
(/^(\.|~){1,2}(\/){1,2}$/.test(url.slice(0,3))
this part checks if the path string starts with the "./" or "../" or "~/". If it does, Boolean true is returned. Otherwise the next test is executed.
这部分检查路径字符串是否以“./”或“../”或“~/”开头。如果是，则返回布尔值 true。否则执行下一个测试。
/(\/){1,2}(\.){1,2}(\/){1,2}/.test(url)
This just checks if the path string has either "/./" or "/../". and returns true on any and false on neither.
这只是检查路径字符串是否包含“/./”或“/../”。并在任何情况下都返回 true ，在任何情况下都返回 false 。
If any of the two tests is true then the path string is relative.
如果两个测试中的任何一个为真，则路径字符串是相对的。
For windows.
对于窗户。
isRelative(url){
return (/^(\.){1,2}(\){1,2}$/.test(url.slice(0,3)) ||
/(\){1,2}(\.){1,2}(\){1,2}/.test(url));
}
