const hash = (str) => {
  let val = 0;
  const strlen = str.length;

  if (strlen === 0) { return val; }

  for (let i = 0; i < strlen; ++i) {
    const code = str.charCodeAt(i);
    val = ((val << 5) - val) + code;
    val &= val; // Int32
  }
  return (val >>> 0); // uInt32
};

// usage
const myHash = hash("Hello, world"); // 3818678700