node:string_decoder

Bundled source can use the documented Node 24 streaming decoder directly:

import { Buffer } from 'node:buffer';
import { StringDecoder } from 'node:string_decoder';

const decoder = new StringDecoder('utf8');

export function decode() {
    return decoder.write(Buffer.from([0xf0, 0x9f])) + decoder.end(Buffer.from([0x8c, 0x8d]));
}

Jco maps the import to a guest-local implementation based on Node 24.20.0. It retains incomplete UTF-8, UTF-16LE, base64, and base64url groups between calls, supports Node’s encoding aliases, and accepts strings or any ArrayBufferView. It reuses the audited Buffer core already used by node:buffer; it does not add a WIT import, callback export, host adapter, or JSPI operation.

Because the adapter is selected only when bundled code resolves node:string_decoder, source graphs that do not import it pay no decoder code or initialization cost. The bare string_decoder name follows normal package resolution before falling back to this builtin.