ECMAScript insiders say the new features present complicated problems but are optimistic about their inclusion in future versions of JavaScript ... Long-planned async capabilities are on the ...

Asynchronous programming is essential to modern JavaScript development by enabling applications to remain responsive and efficient even while performing lengthy operations such as network requests ...

But in general, I think it is better to talk about the AMD (Asynchronous Module Definition) loader ecosystem as a whole [providing a building block for referencing modular JavaScript code].