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bad Buffer conversion behaviour due to Uint8Array inheritance #28725
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Buffer.from(new Uint32Array([0x4701c993]).buffer)😄Reacted by Luigi PincaHow about introducing a new API like
Buffer.fromBufferView(bufferView: ArrayBufferView)to a shorthand ofBuffer.from(bufferView.buffer, bufferView.byteOffset, bufferView.byteLength)?I saw a lot of
Buffer.from(uint8array)forUint8Array-to-Bufferconversion, but because it copies the underlying buffer it is not the best solution for the most cases.(
ArrayBufferViewhere is an object thatArrayBuffer.isView()returns true).Also, maybe we could emit a warning for this? That's platform independent and if someone does
Buffer.from(new Uint32Array(...))they almost certainly have a bug.- added a commit that references this issue
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tl;dr - TypedArrays of lower-order truncate high-order values, which is is confusing (and hard to work around).
Ok so
Buffer.from(new Uint32Array([0x4701c993]))returns a buffer with a length of1and a value in index0of0x93.This is a bad conversion and seems obviously wrong to me. An explicit 32-bit type was provided, and not just
[0x4701c993](for which the docs says interpreted as octets).I don't possibly see how this could be the desired behavior, the resulting values are nothing like the input at all. But, here's the spec: https://www.ecma-international.org/ecma-262/6.0/#sec-touint8
Also, the
Buffer#write<U><Type><Size><endian>()APIs help little, since they are awkwardly designed when used for such a purpose. (They return bytes written and not the buffer.) Presumably, if I had a whole array of int32s I'd have to write some kind of custom converter, which seems wrong considering we are converting to a runtime standard object from a primitive type.Suggestion: fix this somehow, or, provide a nicer API to do a reasonable conversion.