Promises

[3goats]

Hi,

I've been using Bluebird in some of my other ECMA5 projects to provide support for promises. I'm looking to build a new project using ECMA6 and will need support for Promises. Since the whole ECMA6 and 6to5 thing is still so new, I'm struggling to understand the best way to add this to my project.

Do I just use Bluebird as per my ECMA5 code or is there a good way to do this using 6to5 ?

This is an example of my working my ECMA5 code:

var Promise = require("bluebird");
var Request = Promise.promisify(require('request'));

function callhttp(host) {

    var cert = " ";

    var options = {
        url: 'https://' + host,
        method: "GET",
        headers: {
            'User-Agent': 'request'
        }
    };

    return Request(options).spread(function (response, body) {
        if (response.statusCode == 200) {
           // console.log(body)
            console.log(response.connection.getPeerCertificate().subject.CN)
            return {
                CN: response.connection.getPeerCertificate().subject.CN,
            };
        } else {
            // Just an example, 200 is not the only successful code
            throw new Error("HTTP Error: " + response.statusCode);
        }
    });
}


var join = Promise.join;
join(
    callhttp("www.google.com"),
    callhttp("www.microsoft.com"),
    callhttp("www.adobe.com"),
    function (first, second, third) {
        console.log([first, second, third]);
    });

[sebmck]

If you're using bluebird then there's no real reason to stop. It provides a superset of the features and methods available in ES6 Promises so you're likely going to be relying on some of those already.

[stefanpenner]

It provides a superset of the features

/pedantic statement

actually it is an improper superset, more like c <-> c++. As it diverges in some scenarios, including subclassing. But don't let me scare you from it, bluebird is a rock solid promise implementation.

/#pedantic statement

[sebmck]

@stefanpenner Ah great, thanks for the clarification. I'm not familiar with the Promise ecosystem as much as I'd like.

[stefanpenner]

If people don't utilize the a good proportion of the feature set, it may be slightly byte size heavy. But the 2-4 extra TCP packets it costs I doubt hurt anyone. In most cases, the cost of thinking saving those bytes is higher.

[3goats]

Thanks for the input here guys. Very helpful.