Deep copy

deep-copy.ts

export function deepClone<T>(obj: T): T {
  let copy;

  if (null === obj || 'object' !== typeof obj) {
    return obj;
  }

  if (obj instanceof Date) {
    copy = new Date();
    copy.setTime(obj.getTime());
    return copy;
  }

  if (obj instanceof Array) {
    copy = [];
    for (let i = 0, len = obj.length; i < len; i++) {
      copy[i] = deepClone(obj[i]);
    }
    return copy;
  }

  if (obj instanceof Object) {
    copy = {};
    for (let attr in obj) {
      if (obj.hasOwnProperty(attr)) {
        copy[attr] = deepClone(obj[attr]);
      }
    }
    return copy;
  }

  throw new Error('Unable to copy');
}