I refactored the example quickstart code provided on Azure's cognitive API

1-search.js

// Original doc on https://docs.microsoft.com/en-us/azure/cognitive-services/bing-web-search/quickstarts/nodejs#make-a-request-and-print-the-response
// This will not run because the doc's ordering led me to call an undefined method

// Use strict mode.
'use strict';

// Require the https module.
let https = require('https');

// Replace with a valid subscription key.
let subscriptionKey = 'enter key here';

/*
 * Verify the endpoint URI. If you
 * encounter unexpected authorization errors, double-check this host against
 * the endpoint for your Bing Web search instance in your Azure dashboard.
 */
let host = 'api.cognitive.microsoft.com';
let path = '/bing/v7.0/search';
let term = 'Microsoft Cognitive Services';

// Validate the subscription key.
if (subscriptionKey.length === 32) {
    bing_web_search(term);
} else {
    console.log('Invalid Bing Search API subscription key!');
    console.log('Please paste yours into the source code.');
}

let response_handler = function (response) {
    let body = '';
    response.on('data', function (d) {
        body += d;
    });
    response.on('end', function () {
        console.log('\nRelevant Headers:\n');
        for (var header in response.headers)
            // Headers are lowercased by Node.js.
            if (header.startsWith("bingapis-") || header.startsWith("x-msedge-"))
                 console.log(header + ": " + response.headers[header]);
        // Stringify and parse the response body.
        body = JSON.stringify(JSON.parse(body), null, '  ');
        console.log('\nJSON Response:\n');
        console.log(body);
    });
    response.on('error', function (e) {
        console.log('Error: ' + e.message);
    });
};

let bing_web_search = function (search) {
    console.log('Searching the Web for: ' + term);
        // Declare the method, hostname, path, and headers.
        let request_params = {
            method : 'GET',
            hostname : host,
            path : path + '?q=' + encodeURIComponent(search),
            headers : {
                'Ocp-Apim-Subscription-Key' : subscriptionKey,
            }
        };
    // Request to the Bing Web Search API.
    let req = https.request(request_params, response_handler);
    req.end();
}

2-search.js

// Usage:
//
//   node search.js "My awesome query"
//
const https = require('https')

// HOWTO: set an environment variable https://is.gd/zu55jA
const API_KEY = process.env['AZURE_API_KEY']
const API_URL = 'https://api.cognitive.microsoft.com/bing/v7.0/search'

function bingWebSearch(query) {
  https.get(`${API_URL}?q=${encodeURIComponent(query)}`, {
    headers: {
      'Ocp-Apim-Subscription-Key': API_KEY
    }
  }, res => {
    let body = ''
    res.on('data', part => body += part)
    res.on('end', () => {
      for (var header in res.headers) {
        if (header.startsWith("bingapis-") || header.startsWith("x-msedge-")) {
          console.log(header + ": " + res.headers[header])
        }
      }
      console.log('\nJSON Response:\n')
      console.log(JSON.stringify(JSON.parse(body), null, '  '))
    })
    res.on('error', e => {
      console.log('Error: ' + e.message)
      throw e
    })
  })
}

const query = process.argv[2] || 'Microsoft Cognitive Services'
bingWebSearch(query)

Signature of get was different for me. Modified it slightly and also threw an error on a missing env var. Tested it on node 6 and 10

// Usage:
//
//   node search.js "My awesome query"
//
const https = require('https')

// HOWTO: set an environment variable https://is.gd/zu55jA
const API_KEY = process.env['AZURE_API_KEY']
if (!API_KEY) {
  throw new Error('Missing the AZURE_API_KEY environment varable')
}

function bingWebSearch(query) {
  https.get({
    hostname: 'api.cognitive.microsoft.com',
    path:     '/bing/v7.0/search?q=' + encodeURIComponent(query),
    headers:  {
      'Ocp-Apim-Subscription-Key': API_KEY
    },
  }, res => {
    let body = ''
    res.on('data', part => body += part)
    res.on('end', () => {
      for (var header in res.headers) {
        if (header.startsWith("bingapis-") || header.startsWith("x-msedge-")) {
          console.log(header + ": " + res.headers[header])
        }
      }
      console.log('\nJSON Response:\n')
      console.log(JSON.stringify(JSON.parse(body), null, '  '))
    })
    res.on('error', e => {
      console.log('Error: ' + e.message)
      throw e
    })
  })
}

const query = process.argv[2] || 'Microsoft Cognitive Services'
bingWebSearch(query)

@JoshCheek - indeed, the three arg method requires Node v10.9