Find parent folder with file in node js - node.js

Question

I want to be able to find target.json by passing a path to startingPoint.txt to a function in Node JS, given the following folder structure:
- root
- sub1
- sub2
startingPoint.txt
target.json
I've found a node package for it called find-up, but this is the kind of thing that probably takes no more than 6 lines of code.
export function findUp(start: Path, target: string): Path | undefined {
// this code here
}
const pathToTarget = findUp("root/sub1/sub2/startingPoint.txt", "target.json"/);
console.log(pathToTarget); // "root/target.json"

Answer 1

Old question I know, but I've just had to implement something similar and spent ages trying to find a good solution.
So, for future explorers, heres my solution using path and fs modules.
const PATH = require('path');
const FS = require('fs');
function findInPathAncestry(path, target) {
let current_directory_path = PATH.normalize(path).split(PATH.sep);
let result = false;
while(current_directory_path.length && !result) {
let current_path = current_directory_path.join(PATH.sep)+PATH.sep+target;
if(FS.existsSync(current_path)) {
result = current_path;
}
current_directory_path.pop();
}
return result;
}
usage example:
// example file structure:
// C:\
// | - path\
// | --- to\
// | ----- start\
// | ------- at\
// | ----- findme.txt
let start_location = "C:\path\to\start\at";
let target_file = "findme.txt";
console.log(findInPathAncestry(start_location, target_file));
// expected output:
// C:\path\to\findme.txt
// or false if file doesn't exist in path
the use of PATH.normalize and PATH.sep allows this to work in windows and unix environments
https://nodejs.org/api/path.html#path_path_sep

Answer 2

Here's what I have for now:
import { join, dirname } from 'path';
import { existsSync } from 'fs';
export let MAX_BACK_STEPS = 50;
export function findUp(start: string, target: string, boundary?: {
path: string,
inclusive: boolean,
}): string | null {
let currentDir = dirname(start);
let lastTry = false;
let backSteps = 0;
while (backSteps++) {
if (backSteps >= MAX_BACK_STEPS) {
console.error("Too many back steps");
return null;
}
if (boundary && boundary.path.includes(currentDir)) {
if (boundary.inclusive && lastTry === false) {
lastTry = true;
} else {
return null;
}
}
const targetTestPath = join(currentDir, target);
if (existsSync(targetTestPath)) {
return targetTestPath;
}
currentDir = join(currentDir, "../");
}
}