Async Recursive File System Traversal - node.js

Question

I am trying to compile an array out of data present in some specific files, using a recursive approach to read directories and the file system methods are asynchronous. I am unable to figure out the apt place for the callback invocation.
const fs = require('fs');
const ENTRY = "../a/b";
const FILE_NAME = 'index.json';
var nodes = [];
function doThisOnceDone() {
console.log(nodes);
}
function readFile(path) {
fs.readFile(path + '/' + FILE_NAME,{
encoding:"UTF-8"
}, function(err, data) {
if(err) {
return;
}
nodes.push(data);
});
}
function compileArray(path, callback) {
fs.readdir(path, {
encoding:"UTF-8"
}, function(err, files) {
if(err) {
console.error(err);
return;
}
files.forEach(function(file) {
var nextPath = path + '/' + file;
fs.stat(nextPath, function(err, stats) {
if(err) {
return;
}
if(stats.isDirectory()) {
if(file === 'specific') {
readFile(nextPath);
}
else {
compileArray(nextPath);
}
}
});
});
});
}
compileArray(ENTRY, doThisOnceDone);
When do I know that the recursion tree has been done with , and I can access the nodes array ?

Answer 1

Try this
const util = require('util');
const fs = require('fs');
const stat = util.promisify(fs.stat);
const readFile = util.promisify(fs.readFile);
const readdir = util.promisify(fs.readdir);
const ENTRY = "../a/b";
const FILE_NAME = 'index.json';
var nodes = [];
const compileArray = async (path) => {
try {
const files = await readdir(path);
files.forEach((file) => {
try {
var nextPath = path + '/' + file;
const stats = await stat(nextPath); //check other conditions
if (file === 'specific') {
const data = await readFile(path + '/' + FILE_NAME, {
encoding: "UTF-8"
});
nodes.push(data);
}
} catch (error) {
console.log(error);
}
});
} catch (error) {
console.log(error);
}
}

Answer 2

const util = require('util');
const fs = require('fs');
const stat = util.promisify(fs.stat);
const readFile = util.promisify(fs.readFile);
const readdir = util.promisify(fs.readdir);
const ENTRY = "../a/b";
const FILE_NAME = 'index.json';
var nodes = [];
const compileArray = async (path) => {
try {
const files = await readdir(path);
files.forEach(async (file) => {
try {
var nextPath = path + '/' + file;
const stats = await stat(nextPath); //check other conditions
if (file === 'specific') {
const data = await readFile(path + '/' + FILE_NAME, {
encoding: "UTF-8"
});
nodes.push(data);
}
} catch (error) {
console.log(error);
}
});
} catch (error) {
console.log(error);
}
}
compileArray(ENTRY)