traverseFs.js

const fs = require('fs');
const {join} = require('path');

module.exports = async function traverseFs(path, onFile) {
    const stack = [];
    let i = 0;
    let files = await readdir(path);
    while (i < files.length) {
        const file = files[i];
        if (file.isDirectory()) {
            const nextPath = join(path, file.name);
            const nextFiles = await readdir(nextPath);
            // Skip empty directories
            if (nextFiles.length) {
                stack.push({path, files, i});
                path = nextPath;
                files = nextFiles;
                i = 0;
                continue;
            }
        } else {
            await onFile(join(path, file.name));
        }
        if (i === files.length - 1) {
            let restore;
            do {
                restore = stack.pop();
            } while (
                restore &&
                restore.i === restore.files.length - 1
            );
            if (restore) {
                path = restore.path;
                files = restore.files;
                i = restore.i + 1;
            } else {
                break;
            }
        } else {
            i++;
        }
    }
    function readdir(path) {
        return new Promise((resolve, reject) => {
            fs.readdir(
                path,
                {withFileTypes: true},
                (error, files) => {
                    if (error) {
                        reject(error);
                    } else {
                        resolve(files);
                    }
                },
            );
        });
    }
};