Buffer.from(<ArrayBufferView>)

[LiviaMedeiros]

What is the problem this feature will solve?

Buffer.from() has many different forms, including Buffer.from(arrayBuffer[, byteOffset[, length]]) and Buffer.from(buffer).

However, Buffer.from(abv) does not exist. Depending on exact input, trying to call it with such objects results in false positives, data truncation, data corruption (e.g. double -> unsigned char), thrown TypeErrors and empty buffers.

Creating Buffer from ArrayBufferView's data in userland is extremely error-prone because Buffer.from(arrayBuffer) doesn't copy the data.

What is the feature you are proposing to solve the problem?

Adjust Buffer.from(buffer) to accept not only Buffer and Uint8Array but any ArrayBufferView or at least any TypedArray.

What alternatives have you considered?

Deprecation and removal of Buffer from core into userspace module, with prior porting all core APIs to native Uint8Array/TypedArray/ArrayBufferViews.

[github-actions]

There has been no activity on this feature request for 5 months and it is unlikely to be implemented. It will be closed 6 months after the last non-automated comment.

For more information on how the project manages feature requests, please consult the feature request management document.

[jasnell]

This should be kept open. It's still needed

[addaleax]

@jasnell Is this actionable, though? Buffer.from(abv) has well-defined semantics right now (even if those include data truncation – it matches Uint8Array.from() in that regard, afaict).

[jasnell]

It doesn't need to be Buffer.from(abv) exactly. It can easily be another variation, Buffer.fromTypedArray or such (I'm horrible with naming so other suggestions are welcome)

[addaleax]

Yeah, we could do that. It’s probably worth thinking about the name – it should reflect that it creates the buffer from the underlying memory of a TypedArray rather than its contents – and it’s probably still worth thinking about whether this really makes sense to address in Node.js itself (the fact that writing new Uint8Array(typedArray.buffer, typedArray.byteOffset, typedArray.byteLength) is verbose and repetitive isn’t really a Node.js-specific thing).

[LiviaMedeiros]

Agreed with idea of separate method; its existence by itself would also imply that Buffer.from(abv) does something different.