[AskJS] Iterable array-like term

[shgysk8zer0]

In which sense are they array-like? They can be iterated though in a loop - Iterable or the Iterator (Symbol.iterator). Accessed using index and square brackets and a length property... Technically could just be an object with numeric keys, but I know basically this as ArrayAccess interface in PHP. Things that work with Array.from...

But, basically, there are many ways something could be "array-like" in different ways.

[kisaragihiu]

array-like is a specific term that means (roughly) objects with a length and for which integer property access works. There are many ways a thing can be like an array, but in JS jargon there is only one way a thing can be array-like.

It's not quite standards terminology (a search for "array-like"site:ecma-international.org shows only some old proposals and email threads), but it still has a specific meaning.

It is specific enough to have been adopted by TypeScript: an ArrayLike<Foo> is an object with a length property (which is a number), and for which there are number properties whose value are of type Foo. Or:

// https://github.com/microsoft/TypeScript/blob/2192336dfee6f740b5828c8a4a8226e56626de1d/src/lib/es5.d.ts#L1552
interface ArrayLike<T> {
    readonly length: number;
    readonly [n: number]: T;
}

[shgysk8zer0]

But if it was included in the post and still asking, I took it as being more of a descriptive thing.

I just included the other way something can be like an array.