How convert a string to type Uint8Array in nodejs

Question

• How do I convert a string to a Uint8Array in node?
• I don't normally develop in Javascript and this is driving me nuts. They offer a conversion Uint8Array.toString() but not the other way around. Does anyone know of an easy way for me to do this without creating my own parser?
• I have seen some other answers to this, but they don't seem to address this specific class type

• nezort11: Similar answer for UTF-8 string to UInt8Array stackoverflow.com/questions/18729405/…

Answer 1

You can use Buffer.from(string[, encoding]). The Buffer class has implemented the Uint8Array interface in Node since v4.x. You can also optionally specify an encoding with which to do string processing in both directions, i.e. buffer.toString([encoding]).

Answer 2

Why not simply using:

const resEncodedMessage = new TextEncoder().encode(message)

Answer 3

Uint8Array.from(text.split('').map(letter => letter.charCodeAt(0)));

or (appears about 18% faster):

Uint8Array.from(Array.from(text).map(letter => letter.charCodeAt(0)));

Note: These only work for ASCII, so all the letters are modulo 256, so if you try with Russian text, it won't work.

• Heretic Monkey: Answers with explanation of code generally do better than code dumps which leave it to others to interpret. Also, text.split('') doesn't work well for Unicode strings; see How to get character array from a string?
• Octo Poulos: Well you replied just as I was editing the answer. Indeed it's not good for unicode but this method is very simple and fast and might be exactly what he's looking for.
• Hashbrown: I'd probably just delete that first code snippet as Array.from does respect logical character iteration, and your only issue is charCodeAt, which I would swap to .codePointAt(0) (which can return up to a 32bit number); here you can throw an exception, if you really do expect the codepoints to always be below 512.
• Hashbrown: Btw, this will always work: Uint8Array.from(encodeURI(text).split(/%|(?<!%.?)/).map((x) => ((x[1]) ? parseInt(x, 16) : x.charCodeAt(x))))
• WORMSS: I was just wondering why did you need the array? Cannot you just go straight to Uint8Array.from(text, letter => letter.charCodeAt(0))