Recursive read images files in provided folder - node.js

Question

I am getting folder absolute path and I want to extract all text files path from the folder (recursively).
This is what I've tried:
const fs = require('fs-extra');
const path = require('path');
const getFolderImagesRecursive = async (folderPath) => {
const directoryChildren = await fs.readdir(folderPath);
return directoryChildren.reduce(async (finalArray, directoryChild) => {
const fullPath = path.join(folderPath, directoryChild);
const pathStat = await fs.lstat(fullPath);
if (pathStat.isDirectory()) {
const recursiveResult = await getFolderImagesRecursive(fullPath);
return [
...finalArray,
...recursiveResult,
];
} else if (fullPath.split('.').pop() === 'txt') {
return [
...finalArray,
fullPath,
]
} else {
return finalArray;
}
}, []);
}
For testing purpose I've created dummy folders and text files or folders nested inside. When tried the function on the main test folder I got:TypeError: object is not iterable (cannot read property Symbol(Symbol.iterator)) on line 21.
Does anyone observe the error and can fix it?

Answer 1

The problem is that array.reduce is a synchronous function. And when you pass it an async function the result it gets is a promise. Not an array. The problem is that the finalArray (after the first iteration) is a promise that returns an array. And you're trying to destructure the promise on line 21. You should rewrite your code using loops instead of async/await like this
const fs = require('fs-extra');
const path = require('path');
const getFolderImagesRecursive = (folderPath) => {
const directoryChildren = fs.readdirSync(folderPath);
const finalArray = [];
directoryChildren.forEach(directoryChild => {
const fullPath = path.join(folderPath, directoryChild);
const pathStat = fs.lstatSync(fullPath);
if (pathStat.isDirectory()) {
const recursiveResult = getFolderImagesRecursive(fullPath);
finalArray.concat(recursiveResult);
} else if (fullPath.split('.').pop() === 'txt') {
finalArray.push(fullPath);
}
})
return finalArray;
}
}