normalize.js
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module.exports = function normalize(path) {
var parts = path.split(/(\\+|\/+)/);
if(parts.length === 1)
return path;
var result = [];
var absolutePathStart = 0;
for(var i = 0, sep = false; i < parts.length; i++, sep = !sep) {
var part = parts[i];
if(i === 0 && /^([A-Z]:)?$/i.test(part)) {
result.push(part);
absolutePathStart = 2;
} else if(sep) {
result.push(part[0]);
} else if(part === "..") {
switch(result.length) {
case 0:
// i. e. ".." => ".."
// i. e. "../a/b/c" => "../a/b/c"
result.push(part);
break;
case 2:
// i. e. "a/.." => ""
// i. e. "/.." => "/"
// i. e. "C:\.." => "C:\"
// i. e. "a/../b/c" => "b/c"
// i. e. "/../b/c" => "/b/c"
// i. e. "C:\..\a\b\c" => "C:\a\b\c"
i++;
sep = !sep;
result.length = absolutePathStart;
break;
case 4:
// i. e. "a/b/.." => "a"
// i. e. "/a/.." => "/"
// i. e. "C:\a\.." => "C:\"
// i. e. "/a/../b/c" => "/b/c"
if(absolutePathStart === 0) {
result.length -= 3;
} else {
i++;
sep = !sep;
result.length = 2;
}
break;
default:
// i. e. "/a/b/.." => "/a"
// i. e. "/a/b/../c" => "/a/c"
result.length -= 3;
break;
}
} else if(part === ".") {
switch(result.length) {
case 0:
// i. e. "." => "."
// i. e. "./a/b/c" => "./a/b/c"
result.push(part);
break;
case 2:
// i. e. "a/." => "a"
// i. e. "/." => "/"
// i. e. "C:\." => "C:\"
// i. e. "C:\.\a\b\c" => "C:\a\b\c"
if(absolutePathStart === 0) {
result.length--;
} else {
i++;
sep = !sep;
}
break;
default:
// i. e. "a/b/." => "a/b"
// i. e. "/a/." => "/"
// i. e. "C:\a\." => "C:\"
// i. e. "a/./b/c" => "a/b/c"
// i. e. "/a/./b/c" => "/a/b/c"
result.length--;
break;
}
} else if(part) {
result.push(part);
}
}
if(result.length === 1 && /^[A-Za-z]:$/.test(result))
return result[0] + "\\";
return result.join("");
};