Unclear docs on copying/sharing memory for Buffer.from(arrayBuffer)

[zbjornson]

• Version: v7.4.0
• Subsystem: docs (buffer)

The docs for Buffer.from(arrayBuffer) use the word copy/copying:

• byteOffset Where to start copying from arrayBuffer. Default: 0
• length How many bytes to copy from arrayBuffer. Default: arrayBuffer.length - byteOffset

But as far as I can tell, it always references a subarray and never copies.

The line below it:

When passed a reference to the .buffer property of a TypedArray instance, the newly created Buffer will share the same allocated memory as the TypedArray.

is also confusing -- I think that's meant as an example to emphasize the point that it's shared memory, but to me it sounds like there's a situation when it would copy and not share (e.g. Buffer.from(new ArrayBuffer(8)).

Trivial change but wanted to make sure my understanding was correct before submitting a PR. Something like: "byteOffset - element to begin at", "length - number of elements to include" and adding "For example" to the "when passed a reference..." bit.

[addaleax]

Trivial change but wanted to make sure my understanding was correct before submitting a PR.

You’re right, the docs are not correct. Go for it! :)

If you need a better word to use instead of copying, maybe slicing works. Also, this matches the new TypedArray(buffer [, byteOffset [, length]]); form of the TypedArray constructors, so feel free to link to MDN and/or look there for inspiration. :)