microsoft / microsoft/TypeScript
`IntegerTypedArray` type required for use with `crypto.getRandomValues`
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Description
### ⚙ Compilation target
any
### ⚙ Library
latest
### Missing / Incorrect Definition
The current DOM types `` [are wrong](https://github.com/microsoft/TypeScript-DOM-lib-generator/issues/1194) for `crypto.getRandomValues`. `null` is never accepted, and `ArrayBufferView` is too broad as float arrays also aren't accepted.
However, [fixing](https://github.com/microsoft/TypeScript-DOM-lib-generator/pull/2028) in `TypeScript-DOM-lib-generator` requires conditional inclusion of `BigInt64Array | BigUint64Array` depending on ES2020 availability. I don't think there's a way to fix that within `TypeScript-DOM-lib-generator` without this upstream change in `TypeScript`.
`es5.d.ts`:
```ts
interface IntegerTypedArrayTypes {
Int8Array: Int8Array;
Int16Array: Int16Array;
Int32Array: Int32Array;
Uint8Array: Uint8Array;
Uint16Array: Uint16Array;
Uint32Array: Uint32Array;
Uint8ClampedArray: Uint8ClampedArray;
}
type IntegerTypedArray = IntegerTypedArrayTypes[keyof IntegerTypedArrayTypes];
```
`es2020.bigint.d.ts`:
```ts
interface IntegerTypedArrayTypes {
BigInt64Array: BigInt64Array;
BigUint64Array: BigUint64Array;
}
```
### Sample Code
```TypeScript
// Unused '@ts-expect-error' directive.(2578)
// @ts-expect-error
crypto.getRandomValues(null)
// Unused '@ts-expect-error' directive.(2578)
// @ts-expect-error
crypto.getRandomValues(new Float64Array())
declare const arr: Parameters[0]
const values = crypto.getRandomValues(arr)
// 'values' is possibly 'null'.(18047)
values.BYTES_PER_ELEMENT
// Property 'BYTES_PER_ELEMENT' does not exist on type 'ArrayBufferView'.(2339)
values!.BYTES_PER_ELEMENT
```
### Documentation Link
[10.1.1 The getRandomValues method - Web Cryptography Level 2](https://www.w3.org/TR/webcrypto/#dfn-Crypto-method-getRandomValues)
> If array is not an Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array, then throw a TypeMismatchError and terminate the algorithm.
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