bufferInherit.js

class CustomBuffer {
  constructor(...args) {
    const symBuf = Symbol("Buffer");

    this[symBuf] = Buffer.alloc(...args);

    return new Proxy(this, {
      get(target, prop) {
        return (prop in target)
          ? target[prop]
          : target[symBuf][prop]; // delegate
      }
    });
  }

  hello() {
    console.log("hello");
  }
}

const buf = new CustomBuffer(16);

buf.hello();

for (let val of buf) {
  console.log(val);
}