Simple object serializer

serializer.js

const serialize = (obj) => {
  const type = typeof obj;
  if (obj === null) return 'null';
  else if (type === 'string') return `'${obj}'`;
  else if (type === 'number') return obj.toString();
  else if (type === 'boolean') return obj.toString();
  else if (type !== 'object') return obj.toString();
  else if (Array.isArray(obj)) {
    return `[${obj}]`;
  } else {
    let s = '{';
    for (const key in obj) {
      const value = obj[key];
      if (s.length > 1) s += ',';
      s += key + ':' + serialize(value);
    }
    return s + '}';
  }
};