Pass-through API for NodeJS lambda

demo.js

const https = require('https');

const handler = async (event, context, callback) => {

  const options = {
    host: 'jsonplaceholder.typicode.com',
    path: '/todos/1',
  };

  const postOptions = {
    host: 'jsonplaceholder.typicode.com',
    path: '/todos',
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    }
  };

  // Use promise chaining to put the result of the first promise into the second
  // The resolve in the first promise will be the "todo" variable in the .then
  return new Promise((resolve, reject) => {
    https.get(options, res => {
      var body = '';

      res.on('data', data => {
        body += data;
      })

      res.on('end', () => {
        const jsonData = JSON.parse(body)
        resolve(jsonData)
      })

      res.on('error', function(e) {
        console.error('Error calling external API. ');
        reject('Error calling external API. ');
      });

    })
  }).then(todo => {

    const data = {
      title: "I'm changing the title of the todo with id 1 and posting it back to the API as completed",
      userId: todo.userId,
      completed: true
    }

    const postData = JSON.stringify(data)

    return new Promise((resolve, reject) => {
      const req = https.request(postOptions, res => {

        var body = ''

        res.on('data', data => {
          body += data
        })

        res.on('end', () => {
          const jsonData = JSON.parse(body)
          resolve(jsonData)
        })

        res.on('error', function(e) {
          console.error('Error calling external API. ');
          reject('Error calling external API. ');
        })

      })

      // Pass in the modified object back to the API
      req.write(postData)
      req.end()
    })
  })

}