Interface Crypto does not implement RandomSource, so Crypto.getRandomValues is not generic

[viceice]

TypeScript Version: 2.8.3

Search Terms:

• getRandomValues

Code

crypto.getRandomValues(new Uint32Array(2)).join('')

Expected behavior:
Get a concated string of 2 random uint32.

Actual behavior:
Compiler error:
Property 'join' does not exist on type 'Int8Array | Int16Array | Int32Array | Uint8Array | Uint16Array | Uint32Array | Uint8ClampedArray ...'. Property 'join' does not exist on type 'DataView'.

Looks like microsoft/TypeScript-DOM-lib-generator#278 is not included or overwritten by someone.
I suggest to simply extend the Crypto interface from the RandomSource interface.

Playground Link:

https://www.typescriptlang.org/play/#src=crypto.getRandomValues(new%20Uint32Array(2)).join('')

Related Issues:
#17610

[a-tarasyuk]

@viceice Based on spec - Crypto#getRandomValues, I think, we do not need to extend Crypto interface from the RandomSource interface.

ArrayBufferView getRandomValues(ArrayBufferView array);

getRandomValues returns ArrayBufferView

ArrayBufferView is a helper type representing any of the following JavaScript TypedArray types: Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, Float32Array, Float64Array or DataView. This is a helper type to simplify the specification, it isn't an interface and there are no objects implementing it.
typedef ArrayBufferView

Spec says that ArrayBufferView - is a helper type, and I suppose that it should look like so

type ArrayBufferView = Int8Array | Uint8Array | Uint8ClampedArray | Int16Array | Uint16Array | Int32Array | Uint32Array | Float32Array | Float64Array | DataView;

[viceice]

At typescript 2.7 Crypto interface was defined at lib.d.ts:

interface Crypto extends Object, RandomSource {
    readonly subtle: SubtleCrypto;
}
interface RandomSource {
    getRandomValues<T extends Int8Array | Uint8ClampedArray | Uint8Array | Int16Array | Uint16Array | Int32Array | Uint32Array>(array: T): T;
}

With typescript 2.8 it has changed to

interface Crypto {
    readonly subtle: SubtleCrypto;
    getRandomValues(array: Int8Array | Int16Array | Int32Array | Uint8Array | Uint16Array | Uint32Array | Uint8ClampedArray | Float32Array | Float64Array | DataView | null): Int8Array | Int16Array | Int32Array | Uint8Array | Uint16Array | Uint32Array | Uint8ClampedArray | Float32Array | Float64Array | DataView | null;
}

This looks wrong to me.

[a-tarasyuk]

@viceice Seems that the latest changes follow the spec

[Exposed=(Window,Worker)]
interface Crypto {
  [SecureContext] readonly attribute SubtleCrypto subtle;
  ArrayBufferView getRandomValues(ArrayBufferView array);
};

Crypto does not extend RandomSource.

[viceice]

Ok, aggreed.

At https://www.w3.org/TR/WebCryptoAPI/#Crypto-method-getRandomValues step 4. it says, that it returns the given array.

So maybe we can make this method generic? Like before, but with the new types. So that the return value will be like the given type and not a multi type?

interface Crypto {
    readonly subtle: SubtleCrypto;
    type ArrayBufferView = Int8Array | Int16Array | Int32Array | Uint8Array | Uint16Array | Uint32Array | Uint8ClampedArray | Float32Array | Float64Array | DataView | null;
    getRandomValues<T extends ArrayBufferView = ArrayBufferView>(array: T): T;
}

[mhegazy]

PRs welcomed. You can find more information about contributing lib.d.ts fixes at https://github.com/Microsoft/TypeScript/blob/master/CONTRIBUTING.md#contributing-libdts-fixes.

[mrowles]

I still cannot reference crypto.getRandomValues or straight getRandomValues, throws unknown library in NodeJS after compilation. Has anyone figured this out nicely?