Float16Array's definition is incompatible with other typedarrays

[greggman]

🔎 Search Terms

Float16Array

🕗 Version & Regression Information

• Tried 5.9.2
• I was unable to test this on prior versions because irrelevant

⏯ Playground Link

https://www.typescriptlang.org/play/?target=99#code/KYDwDg9gTgLgBDAnmYcAqzgBMCCUoCGiAwhAHYDOMUArgMYzRwC8AUHB3AD5wCSZMABx5CJclVoNo7TjwCqASwHD8RUpWr1GUGR3lKhxADYEAtilyqxGydt3c+AgIwA2EWvGapOzg8XO3K3UJLWlfHn4YAGYAJndrEO97fQFY+OCvO3C4ADEjCAIYV3TPWyYAenK4OghTU2ABBAALBQo4IyVUCBoYABpm1GB8JhqsYDaCAHciOAomiEmlAHNmwtz8wuKg0tCoOFa4Mgh4GvNChQAjI1RFmCa4Y6ah6p3vCmT1gui47Ztdj7yXxcABYSn9vABuVisUCQWAITDoTCWUQsD6RFSiD7+ITxbEGQTGMwWPHZSJbLHZHEUojo1I-SmyOA4tJWAEbIqBRl6T6FVnchyAwog+JQmHgaAnEwUNoYElWABqCmAkwA4g0hoUmABvewEKwAIRoADNjUMAFxweJG01DKG+C6IGDAADypoowBglrINFMFzt0N8NXB2gAFBQFAAvYD8A1O8be33+qAASjgut8vjurQAdPrRDazXtmIcVVbDSai+GozGyHHnRQU-bMxxsxQc47nW7jR74CWAAzNjgAX3sS09SpVAB40HBQM6yFhZcj4gA+UPEbSWuXYMGJbT9H2mACi13qAgoib9QxT2-T9iDnjgADdlZMWKX35voKG23mK7aUD9H+nauu6nqHr6p7AOeMCNkOmYgfG3a9nAADUJaviqHbxgAMg0Sx3AhvhQJ6NBQGQL5vnABCygho6juKcLwMaNBkAwCjkHA44wJOkwznOIALkuSLyqI675kQhYWuWBaVkM-TflA24rr8+7QLe6D3o+GhUWWJZkGWSmhpJiDSamCGkTA5GUVh760egUKjkAA

💻 Code

export type TypedArrayConstructor =
 | Int8ArrayConstructor
 | Uint8ArrayConstructor
 | Uint8ClampedArrayConstructor
 | Int16ArrayConstructor
 | Uint16ArrayConstructor
 | Int32ArrayConstructor
 | Uint32ArrayConstructor
 | Float16ArrayConstructor // comment this line out, the error codes away showing that Float16ArrayConstructor is not compatible with other constructors
 | Float32ArrayConstructor
 | Float64ArrayConstructor;

export type TypedArray =
 | Int8Array
 | Uint8Array
 | Uint8ClampedArray
 | Int16Array
 | Uint16Array
 | Int32Array
 | Uint32Array
 | Float16Array
 | Float32Array
 | Float64Array;

export class TypedArrayViewGenerator {
 arrayBuffer: ArrayBuffer;
 byteOffset: number;

 constructor(sizeInBytes: number) {
 this.arrayBuffer = new ArrayBuffer(sizeInBytes);
 this.byteOffset = 0;
 }
 getView<T extends TypedArray>(Ctor: TypedArrayConstructor, numElements: number): T {
 // gets an error here because `Float16Array` is not following the
 // the same pattern as the other typed array views
 const view = new Ctor(this.arrayBuffer, this.byteOffset, numElements);
 this.byteOffset += view.byteLength;
 return view as T;
 }
}

export function getView<T extends TypedArray>(arrayBuffer: ArrayBuffer, Ctor: TypedArrayConstructor): T {
 // this gets an error too for the same reason
 const view = new Ctor(arrayBuffer);
 return view as T;
}

🙁 Actual behavior

Float16Array should behave the same as other typed array views like Float32Array, Uint32Array etc... It's not

🙂 Expected behavior

Float16Array behaves the same as other typed array views like Float32Array, Uint32Array etc...

Additional information about the issue

No response

[greggman]

I think maybe one or both of these lines

 new (buffer: ArrayBuffer, byteOffset?: number, length?: number): Float16Array<ArrayBuffer>;
 new (array: ArrayLike<number> | ArrayBuffer): Float16Array<ArrayBuffer>;

need to be added to esnext.float16.d.ts here?

TypeScript/src/lib/esnext.float16.d.ts

Line 359 in 7956c00

I see similar definitions for other typed arrays. For example

TypeScript/src/lib/es5.d.ts

Line 4366 in 7956c00

new (buffer: ArrayBuffer, byteOffset?: number, length?: number): Float64Array<ArrayBuffer>;

[Renegade334]

Looks like the float16 definitions were written prior to #60934 but merged after it, and you're running afoul of the same problem as in the linked issue there. Adding the missing non-generic overloads should indeed solve the problem.