Typescript 5.7.2: Can't extend DataView - TS2508: No Base constructor has the specified number of type arguments

[meszaros-lajos-gyorgy]

🔎 Search Terms

"dataview", "ts2508", "no base constructor has the specified number of type arguments"

🕗 Version & Regression Information

• This changed between versions 5.6.3 and 5.7.2
• This probably changed in commit or PR Make typed arrays generic over ArrayBufferLike #59417
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about DataView and TypedArray
• I was unable to test this on prior versions because _______

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.7.2#code/MYGwhgzhAEAa0FMAeAXBA7AJjAImFYAagJYIDu0A3gL5A

💻 Code

class X extends DataView {}

🙁 Actual behavior

error TS2508: No base constructor has the specified number of type arguments.

🙂 Expected behavior

build should run without any issues and class X should use the default constructor of DataView

Additional information about the issue

No response

[MartinJohns]

This is working as intended, see the release notes and the PR you linked; #59417

DataView is now a generic type accepting one type argument. You don't provide a type argument.

[meszaros-lajos-gyorgy]

@MartinJohns could you please provide an example? I tried the following:

class X extends DataView<Uint8Array> {}

But this gave me another error:

Type 'Uint8Array<ArrayBufferLike>' does not satisfy the constraint 'ArrayBufferLike & { BYTES_PER_ELEMENT?: undefined; }'.
  Type 'Uint8Array<ArrayBufferLike>' is not assignable to type 'ArrayBuffer & { BYTES_PER_ELEMENT?: undefined; }'.
    Type 'Uint8Array<ArrayBufferLike>' is not assignable to type '{ BYTES_PER_ELEMENT?: undefined; }'.
      Types of property 'BYTES_PER_ELEMENT' are incompatible.
        Type 'number' is not assignable to type 'undefined'.

[meszaros-lajos-gyorgy]

Okay, I got it working like this:

class X extends DataView<Uint8Array['buffer']> {}