ArrayBuffer is missing slice() method in lib.d.ts

[philipbulley]

The ArrayBuffer docs on MDN and MSDN show the existence of ArrayBuffer.slice(). This is not currently represented in lib.d.ts (as of ef5ae6e on master).

Existing:

interface ArrayBuffer {
    /**
      * Read-only. The length of the ArrayBuffer (in bytes).
      */
    byteLength: number;
}

Suggested:

interface ArrayBuffer {
    /**
      * Read-only. The length of the ArrayBuffer (in bytes).
      */
    byteLength: number;

    /**
      * Returns a section of an ArrayBuffer.
      */
    slice(begin:number, end?:number): ArrayBuffer;
}

[RyanCavanaugh]

This method is only supported on newer platforms; lib.d.ts is intentionally generated from a more broadly-supported subset of the API.

If you're using this method and your code only needs to run on newer runtimes, you can easily re-open the interface and add the method.

[lukehoban]

IE11 (and other head browsers) support ArrayBuffer.prototype.slice. I believe elsewhere, lib.d.ts includes everything that's part of IE11. For example, lib.d.ts includes Map and Set types. Given that, shouldn't slice be added?

[philipbulley]

lib.d.ts is intentionally generated from a more broadly-supported subset of the API

Just out of interest, how do the Typescript team determine this? I'm assuming there must be a set of agreed upon rules that an API feature is tested against, as opposed to one's opinion?

[RyanCavanaugh]

Talked to @mhegazy about this; the ArrayBuffer and ArrayBufferView are in the small subset of things that aren't automatically generated, so we just missed this one.