There is no proposal for a standard generator, but for the sake of completeness,
if an array iterator consumes an array, an array generator would lazily produce
one.
An array generator object would implement yield as a method with behavior
analogous to the same keyword within a generator function.
The yield method would add a value to the array.
var array = [];
var generator = generate(array);
generator.yield(10);
generator.yield(20);
generator.yield(30);
expect(array).toEqual([10, 20, 30]);Since ECMAScript 5, at Doug Crockford’s behest, JavaScript allows keywords to be
used for property names, making this parallel between keywords and methods
possible.
A generator might also implement return and throw methods, but a meaningful
implementation for an array generator is a stretch of the imagination.
Although an array generator is of dubious utility, it foreshadows the interface
of asynchronous generators, for which meaningful implementations of return and
throw methods are easier to obtain, and go on to inform a sensible design for
asynchronous generator functions.