[Node.js] Efficient File Processing in Node.js with Async Generators and Array.fromAsync

Using the Node.js glob function as a practical example, you'll learn how Array.fromAsync facilitates the creation of arrays from asynchronous iterables and how generators can improve performance in file processing tasks.

import { glob } from "node:fs/promises"
import os from "node:os"
import path from "node:path"

const cwd = path.join(os.homedir(), "dev")
const files = await Array.fromAsync(glob("*", {cwd}))

console.log(files)

 glob("*", {cmd}) return an AsyncIterator, which yields the paths of files that math the pattern.

Array.fromAsync() and Promise.all() can both turn an iterable of promises into a promise of an array. However, there are two key differences:

• Array.fromAsync() awaits each value yielded from the object sequentially. Promise.all() awaits all values concurrently.
• Array.fromAsync() iterates the iterable lazily, and doesn't retrieve the next value until the current one is settled. Promise.all() retrieves all values in advance and awaits them all.