Node.js — How to Download a File

You can download a file in Node.js in different ways. Node.js comes with built-in functions to download and save a file to your local disk. You can combine the integrated https and fs modules to download files from the Internet.

This tutorial shows you how to use native Node.js features to download a file from the Internet to your local computer.

Node.js Series Overview

  1. String Replace All Appearances
  2. Remove All Whitespace From a String in JavaScript
  3. Generate a Random ID or String in Node.js or JavaScript
  4. Remove Extra Spaces From a String in JavaScript or Node.js
  5. Remove Numbers From a String in JavaScript or Node.js
  6. Get the Part Before a Character in a String in JavaScript or Node.js
  7. Get the Part After a Character in a String in JavaScript or Node.js
  8. How to Check if a Value is a String in JavaScript or Node.js
  9. Check If a String Includes All Strings in JavaScript/Node.js/TypeScript
  10. Check if a Value is a String in JavaScript and Node.js
  11. Limit and Truncate a String to a Given Length in JavaScript and Node.js
  12. Split a String into a List of Characters in JavaScript and Node.js
  13. How to Generage a UUID in Node.js
  14. Reverse a String in JavaScript or Node.js
  15. Split a String into a List of Lines in JavaScript or Node.js
  16. Split a String into a List of Words in JavaScript or Node.js
  17. Detect if a String is in camelCase Format in Javascript or Node.js
  18. Check If a String Is in Lowercase in JavaScript or Node.js
  19. Check If a String is in Uppercase in JavaScript or Node.js
  20. Get the Part After First Occurrence in a String in JavaScript or Node.js
  21. Get the Part Before First Occurrence in a String in JavaScript or Node.js
  22. Get the Part Before Last Occurrence in a String in JavaScript or Node.js
  23. Get the Part After Last Occurrence in a String in JavaScript or Node.js
  24. How to Count Words in a File
  25. How to Shuffle the Characters of a String in JavaScript or Node.js
  26. Append Characters or Words to a String in JavaScript or Node.js (Coming soon)
  27. Check if a String is Empty in JavaScript or Node.js (Coming soon)
  28. Ensure a String Ends with a Given Character in JavaScript or Node.js (Coming soon)
  29. Left-Trim Characters Off a String in JavaScript or Node.js (Coming soon)
  30. Right-Trim Characters Off a String in JavaScript or Node.js (Coming soon)
  31. Lowercase the First Character of a String in JavaScript or Node.js (Coming soon)
  32. Uppercase the First Character of a String in JavaScript or Node.js (Coming soon)
  33. Prepend Characters or Words to a String in JavaScript or Node.js (Coming soon)
  1. How to Download a File

Download a File in Node.js

Node.js’ https module allows you to send requests HTTPS requests. The given https.get method accepts the resource URL and an options object. In this example, we’re using the file URL on the Internet and skip the request options because we don’t need them.

The https.get method provides the response instance in a callback function. The response gives you access to the response status code, headers, and payload. Determine whether the request is successful and pipe the response data into a local file.

You can create a write stream piping the response data into a local target file. Here’s a sample function to download a file in Node.js:

import Fs from 'fs'  
import Https from 'https'

/**
 * Download a file from the given `url` into the `targetFile`.
 *
 * @param {String} url
 * @param {String} targetFile
 *
 * @returns {Promise<void>}
 */
async function downloadFile (url, targetFile) {  
  return await new Promise((resolve, reject) => {
    Https.get(url, response => {
      const code = response.statusCode ?? 0

      if (code >= 400) {
        return reject(new Error(response.statusMessage))
      }

      // handle redirects
      if (code > 300 && code < 400 && !!response.headers.location) {
        return resolve(
          downloadFile(response.headers.location, targetFile)
        )
      }

      // save the file to disk
      const fileWriter = Fs
        .createWriteStream(targetFile)
        .on('finish', () => {
          resolve({})
        })

      response.pipe(fileWriter)
    }).on('error', error => {
      reject(error)
    })
  })
}

Notice: the downloadFile function above wraps the https.get method into a promise. You may not need the promise. Modern Node.js code typically uses async/await instead of callbacks. That’s the reason you may want to use promises as well.

Then use the downloadFile method to download content from the Internet. For example, you may want to download a new wallpaper like this:

const targetFile = 'wallpaper.png'  
const wallpaperUrl = 'https://unsplash.com/photos/W-fi1aeE-N8'

await download(wallpaperUrl, targetFile)  

That’s it! Enjoy downloading files in Node.js!


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