jQuery.when()

Provides a way to execute callback functions based on zero or more Thenable objects, usually Deferred objects that represent asynchronous events.

jQuery.Deferred()

A factory function that returns a chainable utility object with methods to register multiple callbacks into callback queues, invoke callback queues, and relay the success or failure state of any synchronous or asynchronous function.

.data()

Store arbitrary data associated with the matched elements or return the value at the named data store for the first element in the set of matched elements.

jQuery.each()

A generic iterator function, which can be used to seamlessly iterate over both objects and arrays. Arrays and array-like objects with a length property (such as a function’s arguments object) are iterated by numeric index, from 0 to length-1. Other objects are iterated via their named properties.