Type 'ArrayBufferLike' is not assignable to type 'BlobPart'.

[Yonom]

🔎 Search Terms

ArrayBufferLike BlobPart SharedArrayBuffer ES2024

🕗 Version & Regression Information

• This changed between versions 5.7.2 and 5.6.3
• This changed in commit or PR ___
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about _____
• I was unable to test this on prior versions because ___

⏯ Playground Link

https://www.typescriptlang.org/play/?target=11&ts=5.7.2#code/MYewdgzgLgBFICEA2IBGMC8MAUATAhlPgFwwCqAlmFABwCCATg-gJ4A0cLADgKanQMqAcwCUmAHwwA3jABQMGAx5QArgzAwwPAO4xkabAG0CRAHSoVAM0s8GAXQ4yo3HjAC+IgNyy3QA

💻 Code

When targetting ES2024, the following code throws a type error:

const toBlob = (data: Uint8Array, type: string) => { 
  return new Blob([data.buffer], { type });
}

🙁 Actual behavior

Type 'ArrayBufferLike' is not assignable to type 'BlobPart'.
  Type 'SharedArrayBuffer' is not assignable to type 'BlobPart'.
    Type 'SharedArrayBuffer' is missing the following properties from type 'ArrayBuffer': resizable, resize, detached, transfer, transferToFixedLength

🙂 Expected behavior

Backwards compatibility with ES2023

Additional information about the issue

No response

[jcalz]

The TS 5.7 release notes and #59417 explain what's going on here. If you want a Uint8Array whose buffer property is a suitable BlobPart you'll have to ask for it explicitly like

const toBlob = (data: Uint8Array<ArrayBuffer>, type: string) => { 
  return new Blob([data.buffer], { type });
}

Playground link

And of course that might have to propagate throughout your code base. Maybe the TS team has a recommendation for how to proceed in general with this sort of thing; the release notes only mention updating node.