Calling token API

Question

I'm calling an API to request token, and making sure i'm not leaving any corners for errors and handle the result appropriately.

It's a web service POST call in general, The code gets credentials, formats them in the URL and parses the result.

The objective here is I'm looking if code overall is good when it comes to REST call, if any corner I'm missing for an error somewhere.

function Authentication() {
}

Authentication.prototype.requestToken = function(credentials) {
    var self = this;
    return new Promise(function(resolve, reject){
        https.request({
            method: 'POST',
            hostname: 'hostname.com',
            path: '/path-to-api' +
                '&client_id=' + credentials.clientId +
                '&client_secret=' + credentials.clientSecret +
                '&device_id=' + credentials.deviceId +
                '&device_token=' + credentials.deviceToken,
            headers: {
                'accept': 'application/json;charset=UTF-8',
                'content-type': 'application/x-www-form-urlencoded'
            }
        }, function(response) {
            var buffers = [];
            response.on('data', buffers.push.bind(buffers));
            response.on('end', function(){
                try {
                    self.token = JSON.parse(Buffer.concat(buffers).toString());
                    response.statusCode == 200 ? resolve(self.token) : reject(self.token);
                } catch (error) {
                    reject(error);
                }
            });
        }).on('error', reject).end();
    });
};

Authentication.prototype.token;

Answer 1

A few minor quibbles:

• You should always have a try-catch inside a new Promise, otherwise exceptions are swallowed.
• Query parameters should be escaped
• "new Promise" should be a rare sight. Never use it directly. Always wrap the thing you want to use with a promise interface (in this case, it's the https library)

And a major quibble:

• This code is stuck in the past. You can simplify greatly if you embrace newer versions of javascript, and maybe add a couple of packages

For example:

const rp = require('request-promise')

class Authentication{
    constructor(){
        this.token = null
    }

    async requestToken(credentials){
        const token = await rp({
            method: 'POST',
            uri: 'https://hostname.com/path-to-api',
            json: true,
            qs: {
                client_id: credentials.clientId,
                client_secret: credentials.clientSecret,
                device_id: credentials.deviceId,
                device_token: credentials.deviceToken,
            },
            headers: {
                'accept': 'application/json;charset=UTF-8',
                'content-type': 'application/x-www-form-urlencoded'
            }
        })

        this.token = token
        return token
    }
}