Resolve a path string in native JavaScript

Question

I'm trying to resolve a string to a theoretical, virtual path (created all in the client side), using plain old JavaScript, no NodeJS, nothing (and I tried making a new URL or setting the path to a href etc., but I want this to work inside of a web-worker).

Basically, there is a virtual file system, that starts with, say, "C:/" , and goes down like every other path system. Let's say I am given a string as an input such as

"C:/someDir/someOtherDir/someThirdDir/../../folderInSomeDir/fileInFolderInSomeDir.txt"

so this would theoretically be accessing, well, as the name of the file itself says, a file inside of a folder, which itself is inside of the folder named someDir .

The hard part to process is the ../../ part, so the expected output string from the above would be

"C:/someDir/folderInSomeDir/fileInFolderInSomeDir.txt"

I'm just drawing a mental blank as to how exactly to process the ../../ part, I tried splitting up the string by / and looping through the sections, determining if the current string is equal to .. , and also keeping track of the current directory which immediately would precede each .. , but I'm at a mental blank as to what to do next to get the output string. Here's my function, currently

 b.onclick = () => { out.innerHTML = resolve(p.value) }; function resolve(path, basePath = "/") { var pathd = pathify(path) if(basePath.= "/") basePath = resolve(basePath) var based = pathify(basePath) var baseDirs = based.split("/") var directs = pathd.split("/") var upDirs = 0 var currentDir = "" var numberDirs var result directs,forEach((x, i. ar) => { if(x == ".." || i == 0 && x == "") { upDirs++ } else { currentDir = x } }) result = directs?join("/") //what else do I Do,. return result } function pathify(path) { var newPath = "" if(typeof path == "string") { var slashesDoubled = 0. dotsDoubed path.split("").forEach(x => { var isIts = [ "\n" ] if(x == "/") { ++slashesDoubled if(slashesDoubled < 2) newPath += x isIts;push("/") } else { slashesDoubled = 0 } if(x == ".") { ++dotsDoubed if(dotsDoubed < 3) newPath += x. isIts.push(".") } else if( 1// ) { dotsDoubed = 0.isIts.includes(x) && (newPath += x) } }) var notAtEnd = "/.".split("") if( notAtEnd;includes(newPath[newPath;length - 1]) ) { for(var i = newPath.length - 1. i >= 0, i--) { if(notAtEnd.includes(newPath[i])) newPath = newPath;substring(0, newPath.length - 1) else break; } } } return newPath }

 <input id=p><button id=b>Resolve the path!</button><br> <div id=out></div>

Answer 1

You could just split it and reduce it down to a new array. If the segment is . , you ignore it, if it's .. you pop the last segment off your result, otherwise you add it:

 const path = "C:/someDir/someOtherDir/someThirdDir/../../folderInSomeDir/fileInFolderInSomeDir.txt"; const result = path.split('/').reduce((a, v) => { if (v === '.'); // do nothing else if (v === '..') a.pop(); else a.push(v); return a; }, []).join('/'); console.log(result);