Hook Write Stream

hook-write-stream.js

const hookStreamWrite = (stream, callback) => {
  const oldWrite = stream.write;
  stream.write = callback((...args) => oldWrite.apply(stream, args));
  return () => {
    stream.write = oldWrite;
  };
};

/* Example */

// 1
console.log('1');

// useful for transforming or redirecting: stdout, stderr
const unhook = hookStreamWrite(process.stdout, (stdout) => (string, encoding, fd) => {
  return stdout(`stdout: ${ string }`);
});

// stdout: 2
console.log('2');

unhook();

// 3
console.log('3');