Capture stdout with callback

capture_stream_2.ts

import { WriteStream } from 'tty';

type callback = (error: Error | null | undefined) => void;

export const captureStream = (stream: WriteStream, nextLines: number, ccb: (data: string) => void): void => {
    const oldWrite = stream.write;
    let output = '';
    let lines = 0;
    stream.write = (chunk: unknown, encoding: string | callback, cb?: callback): boolean => {
        const c = chunk.toString();
        for (let i = 0; i < c.length; i++) {
            if (c[i] === '\n') {
                lines++;
            }
        }
        output += c;
        const r = oldWrite.apply(stream, cb ? [chunk, encoding, cb] : [chunk, encoding, cb]);
        if (lines >= nextLines) {
            stream.write = oldWrite;
            ccb(output);
        }
        return r;
    }
}