Elipsis in front of Angular2 Classes (Collections in this case)

Question

Why are there in many examples elipsis, or three dots in front of an Angular2 Import.

It doesn't seem to be required, I can remove them and my application will still work. I saw this "pattern" in angular2 examples and in the seed I'm using.

I however would like to understand why this is done, I'm not sure if I'm looking for the wrong phrases because I've tried to look this up multiple times before.

providers: [...FORM_PROVIDERS],
directives: [ ...ROUTER_DIRECTIVES]

seems to be the same as

providers: [FORM_PROVIDERS],
directives: [ROUTER_DIRECTIVES]

Is it just for clarifying these are multiple providers/components?

Answer 1

From my comments above.

What you call ellipsis is the ES2015 spread operator.

Otherwise, FORM_PROVIDERS , ROUTER_DIRECTIVES and others are basically arrays of providers, they're just spread in a new array instance. This allows you to pass a flat array of providers if you add multiple of those.