How Can I Download Files in Node.js Without Using External Libraries?

File Download in Node.js Without External Libraries

Downloading files in Node.js can be accomplished natively without relying on external libraries. Here's how:

Using the Built-in Fetch API (Node 18 )

Node 18 introduces the fetch global that implements the Fetch API. This API provides methods to download data, including text, JSON, and binary data. For example:

const fetch = require('node-fetch');

const url = 'http://example.com/file.jpg';
const response = await fetch(url);
const buffer = await response.arrayBuffer();

fs.writeFileSync('filename.jpg', Buffer.from(buffer));

Using HTTP GET Requests (Older Node Versions)

Prior to Node 18, you can create an HTTP GET request and pipe its response into a file stream:

const http = require('http');
const fs = require('fs');

const file = fs.createWriteStream('file.jpg');
const url = 'http://i3.ytimg.com/vi/J---aiyznGQ/mqdefault.jpg';
const request = http.get(url, (response) => {
  response.pipe(file);
});

// Close file stream after download completes
file.on('finish', () => {
  file.close();
  console.log('Download completed');
});

Configuring Command Line Options

If you require command-line options such as specifying a target file or URL, you can utilize a package like Commander for customization:

const program = require('commander');

program
  .option('-o, --output <file>', 'Output file name')
  .option('-u, --url <url>', 'URL to download from')
  .parse(process.argv);

const file = fs.createWriteStream(program.output || 'default.jpg');
const request = http.get(program.url, (response) => {
  response.pipe(file);
});

For more detailed information and alternative approaches, refer to the following resource: https://sebhastian.com/nodejs-download-file/

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