base64/hex methods missing from Uint8Array

[dontwanttothink]

🔎 Search Terms

• toBase64

🕗 Version & Regression Information

• This is the behavior in v5.9.0-dev.20250512.

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.9.0-dev.20250512#code/KoSwdgLgHAggTnAhgTwHQDM4HsC2AhRAZwFMA2AFgAoBKAKFElgRQ2xwAliAPG+8aeEjQAHbBCwRkw4qhIQAYmwIkKvBgOYixEqTLmLcnHnXVMhqURJ3TU45WSon+ZlpfGSb4ozSA

💻 Code

Uint8Array.fromBase64()
Uint8Array.fromHex()
Uint8Array.prototype.setFromBase64()
Uint8Array.prototype.setFromHex()
Uint8Array.prototype.toBase64()
Uint8Array.prototype.toHex()

🙁 Actual behavior

Property XXX does not exist … errors in each case.

🙂 Expected behavior

Correct type definitions should exist.

Additional information about the issue

These features have been implemented by every major JavaScript engine except V8.

See:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/toBase64#browser_compatibility (where it is marked, "Limited availability")

See also:

• base64/hex methods missing from Uint8Array #60743
• base64/hex methods missing from Uint8Array #60612

[MartinJohns]

I wouldn't say it's widely supported when basically the engine with over 90 % market does not support it.

[dontwanttothink]

V8 does not have a market share of over 90%. TypeScript is also used for browser code.

[RyanCavanaugh]

TypeScript is also used for browser code.

V8 is also Chrome and Edge's runtime, so it's a very big problem if it's not there.

[dontwanttothink]

Note that, in the case of DOM APIs, type definitions seem to be generated automatically once two major engine implementations exist. I don't see why this standard JavaScript feature should be different. (Isn't this also the point of having an 'ESNext' library?)

[dontwanttothink]

Further note that Chromium is working on shipping: https://issues.chromium.org/issues/42204568. The omission in TypeScript will need to be fixed soon (and will definitely be). Representing UInt8Arrays as hexstrings is very common when working with modern web APIs (both server- and client-side) because they are frequent as return values and are otherwise difficult to serialize.

[dontwanttothink]

I submitted a PR for this issue: #61696