Question

I have two (slow loading) data sources. I can start working on data source 2 as soon as it’s loaded, but need the data from both 1 and 2 to work on data from source 1. So I have some code like this:

$.get 'url2', (data2) ->
    $.get 'url1', (data1) ->
        # do stuff with data1 and data2
    # do stuff with data2

But, I want to load them in parallel, instead of sequentially (i.e. I don’t want to wait for data source 2 to load before starting to load data source 1).

Are there any nice design patterns to do this?

Answer 1

var one = $.get 'url1'
var two = $.get 'url2'
$.when(one, two).then #both
$.when(two).then #just two

use the new $.when from jQuery 1.5.

here your loading them both in parallel. And using the “promises” returned from $.get to run some function once they are ready.