A javascript-only (esm/cjs) utf8 codec that is abstract-encoding compatible, well-tested and pretty efficient. Bonus: It doesn't use Nodejs' Buffer object and comes with typescript types.
import { encode, encodingLength, decode } from 'utf8-codec' // require works too!
const str = 'Hello World / こんにちは世界'
const bytes = encode(
str,
new Uint8Array(endcodingLength(str)), // own buffer supplied, optional
0 // offset, at which to write the str, optional
)
str === decode(bytes, 0, bytes.length)The TextEncoder and TextDecoder classes exist to encode utf8 strings but they are not optimized for bigger byte processing and don't offer APIs to figure out how preemptively how many bytes are supposed to be written/read. Surprisingly this algorithm is even faster.
The other implementations found at the time do either not implement the edge cases properly and/or both directions of the codec.