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How To Download A File With Node.js
Over the weekend I made a dependency update of my time tracking app “Tie Tracker” (PWA / GitHub).
In this particular tool, I defer the heavy work to Web Workers so that the UI does not find itself in a blocking state.
Because the app is meant to work offline and, is available in the App Store and Google Play, I did not import the required workers’ dependencies through a CDN but, locally.
importScripts('./a-third-party-library.min.js');The app itself is developed with React but, I implemented the workers with vanilla JavaScript and no package manager to handle their dependencies.
Therefore, I had to come with a solution to update the libs with a Node.js script 😇.
Node Fetch
There is no window.fetch like API in Node.js but, there is a light-weight module that brings such capabilities. That’s why I used node-fetch to implement the download of the file.
npm i node-fetch --save-devScript
The script I developed to update my dependencies is the following:
const {createWriteStream} = require('fs');
const {pipeline} = require('stream');
const {promisify} = require('util');
const fetch = require('node-fetch');
const download = async ({url, path}) => {
const streamPipeline = promisify(pipeline);
const response = await fetch(url);
if (!response.ok) {
throw new Error(`unexpected response ${response.statusText}`);
}
await streamPipeline(response.body, createWriteStream(path));
};
(async () => {
try {
await download({
url: 'https://unpkg.com/...@latest/....min.js',
path: './public/workers/libs/....min.js',
});
} catch (err) {
console.error(err);
}
})();The above download function uses a stream pipeline to download a file, as displayed in the node-fetch README, and the built-in fs module to write the output to the file system.
Top Level Await is available as of Node.js v14.8.0 but, I used an immediate function because I integrated it in a chain in which it was not available yet.
That’s it 🥳
Continue Reading
If you want to read more about React and Web Workers, I published back to back three blog posts about it last year 😉.
To infinity and beyond!
David
You can reach me on Twitter or my website.
Give a try to DeckDeckGo for your next presentations 🤟.
