Documentation for creating a Buffer which shares a TypedArray's memory is misleading #31348

• Version: v12.13.0
• Platform: Windows 10 64-bit
• Subsystem: docs

The documentation for Buffer reads, in part (abbreviated for clarity):

It is possible to create a new Buffer that shares the same allocated memory as a TypedArray instance by using the TypedArray object's .buffer property.

const arr = new Uint16Array(2);
arr[0] = 5000;
arr[1] = 4000;
const buf2 = Buffer.from(arr.buffer);
console.log(buf2);
// Prints: <Buffer 88 13 a0 0f>

This works in this case, but I think it's hazardous advice for arbitrary TypedArrays because the backing ArrayBuffer could extend beyond the bounds of the TypedArray which is providing a view of it. For example:

const arrA = Uint8Array.from([0x63, 0x64, 0x65, 0x66]) // 4 elements
const arrB = new Uint8Array(arrA.buffer, 1, 2) // 2 elements
console.log(arrA.buffer === arrB.buffer) // true

const buf = Buffer.from(arrB.buffer)
console.log(buf)
// expected, based on documented advice: <Buffer 64 65>
// actual: <Buffer 63 64 65 66>

It might be better to have the docs suggest Buffer.from(arr.buffer, arr.byteOffset, arr.byteLength) as the general solution to this problem.