Any ideas on an async directory search using fs.readdir? I realise that we could introduce recursion and call the read directory function with the next directory to read, bu
This one uses the maximum amount of new, buzzwordy features available in node 8, including Promises, util/promisify, destructuring, async-await, map+reduce and more, making your co-workers scratch their heads as they try to figure out what is going on.
No external dependencies.
const { promisify } = require('util');
const { resolve } = require('path');
const fs = require('fs');
const readdir = promisify(fs.readdir);
const stat = promisify(fs.stat);
async function getFiles(dir) {
const subdirs = await readdir(dir);
const files = await Promise.all(subdirs.map(async (subdir) => {
const res = resolve(dir, subdir);
return (await stat(res)).isDirectory() ? getFiles(res) : res;
}));
return files.reduce((a, f) => a.concat(f), []);
}
getFiles(__dirname)
.then(files => console.log(files))
.catch(e => console.error(e));
Updated for node 10+ with even more whizbang:
const { resolve } = require('path');
const { readdir } = require('fs').promises;
async function getFiles(dir) {
const dirents = await readdir(dir, { withFileTypes: true });
const files = await Promise.all(dirents.map((dirent) => {
const res = resolve(dir, dirent.name);
return dirent.isDirectory() ? getFiles(res) : res;
}));
return Array.prototype.concat(...files);
}
Note that starting with node 11.15.0 you can use files.flat()
instead of Array.prototype.concat(...files)
to flatten the files array.
If you want to blow everybody's head up completely, you can use the following version using async iterators. In addition to being really cool, it also allows consumers to pull results one-at-a-time, making it better suited for really large directories.
const { resolve } = require('path');
const { readdir } = require('fs').promises;
async function* getFiles(dir) {
const dirents = await readdir(dir, { withFileTypes: true });
for (const dirent of dirents) {
const res = resolve(dir, dirent.name);
if (dirent.isDirectory()) {
yield* getFiles(res);
} else {
yield res;
}
}
}
Usage has changed because the return type is now an async iterator instead of a promise
;(async () => {
for await (const f of getFiles('.')) {
console.log(f);
}
})()
In case somebody is interested, I've written more about async iterators here: https://qwtel.com/posts/software/async-generators-in-the-wild/