Promise.all() work around for IE 11 with Backbone

Question

Background: I have been tasked to help resolve an issue with the following error:

'Promise' is undefined'

Which is part of our sessionsmodel.js script:

return Promise.all(promises);

promises is an array of actions that need to happen and if any fail it is rejected.

Question: Based on my research IE does not support Promise so is there a work around that can be applied to this return value that will accomplish the same thing?

Answer 1

Since you are using Backbone, the promises are probably jQuery promises. You could use jQuery .when function to do the same as Promise.all:

return $.when.apply($, promises);

For most other simple situations where you call functions like save and fetch, you could avoid promises completely by using the provided callbacks:

model.save({
    context: this,
    success: this.onModelSuccess
});

There's no need to use another library because Backbone uses jQuery already (by default), unless you don't like jQuery deferred or that you're using something else in place of jQuery.

Answer 2

ES6 Promise spec was implemented by "good" libraries like Q, When, RSVP, Bluebird, Lie and more...

If you want to learn more on Promises, check this link: Promises