Its funny, when I landed my first job as a software developer, in a statistical startup, I learned about promises using d3.queue[1]. This was before javascript had native promises, and around the javascript community was settling on A+ promises. But d3 was how I learned to write asynchronous code without relying solely on callbacks.

[1]: https://github.com/d3/d3-queue

Likewise, but in jQuery, which in one version introduced a feature where you could add listeners to an ajax request and it'd get called after the response returned - I was like what? how? whoa!?

I'd suggest thanking the developers instead. :)

You are right. Much thanks to mbostock, curran, micahstubbs, jefkoslowski, gordonwoodhull, and baerrach.

sarcasm? who cares about D3's data loading APIs... i mean most sophisticated JS apps using D3 wouldn't use D3 for data fetching from the service.

https://github.com/d3/d3-queue has 1360 stars and gets 50% as many daily downloads as d3 itself, so I wouldn't be too sure that nobody out there is using d3's async facilities.