How to make HTTP requests in Node.js without installing external libraries

When working with Node.js, there are many libraries that support creating requests to another server, such as node-fetch, phin, got or request (deprecated)...

However, if your server simply serves as an API for a client app and you now need to request a JSON file from another server or simply fetch an external API, which library should you choose to use?

The answer is that you don't need to add a new dependency to your package.json just for creating a request because Node.js has a built-in module called https.

HTTPS

https is a lightweight module that comes pre-built in Node.js and is supported in most Node.js versions.

You can create a request using https as follows:

let https = require('https')
 
https
  .get(url, (res) => {
    let body = ''
    res.on('data', (chunk) => (body += chunk))
    res.on('end', () => {
      try {
        let json = JSON.parse(body)
        // Now you can use json data...
      } catch (err) {
        console.error(`Failed to parse JSON data - ${err.toString()}`)
      }
    })
  })
  .on('error', (err) => {
    console.error(`Failed to make request! Error: ${err.toString()}`)
  })

In the code above:

• https is a built-in module in Node.js so you can require it directly without the need for installation.
• You can create a request using https.get(url[, options][, callback]).
• In the callback, you listen to the response events using res.on().
• Each time res.on("data") is triggered, you add the data to the string body.
• When res.on("end") is triggered, you can simply parse the body into a JSON object using JSON.parse(body).
• Lines 8 and 11: Note that you should parse the data within a try {} catch() {} block to catch errors if the JSON cannot be parsed.
• If the request fails, the error event will be triggered.

That's it! Now let's abstract this logic into a function that can be used anywhere in the server:

let https = require('https')
 
let fetchJSON = (url) => {
  return new Promise((resolve, reject) => {
    https
      .get(url, (res) => {
        let body = ''
        res.on('data', (chunk) => (body += chunk))
        res.on('end', () => {
          try {
            resolve(JSON.parse(body))
          } catch (err) {
            reject(err)
          }
        })
      })
      .on('error', reject)
  })
}
 
module.exports = fetchJSON

And you can use it as follows:

// Async context
let data = await fetchJSON(url)
 
// Use the data...

Good luck!