deep copy js

deep_copy.js

// correct object cloning
function clone(obj, fields) {
	if (null == obj || "object" != typeof obj) return obj;
	if (obj.constructor == File && obj.size)
		return obj
	var copy = obj.constructor();

	if (fields){
		for (let i of fields)
			if (obj.hasOwnProperty(i))
				copy[i] = clone(obj[i])
	} else {
		for (let attr in obj)
			if (obj.hasOwnProperty(attr))
				copy[attr] = clone(obj[attr]);
	}

	return copy;
}

const deep_copy = (obj, keys=null) => {
      if (obj===null || typeof(obj) !== 'object') {return obj}
      if (obj.constructor == File && obj.size) {return obj}
      const copy = obj.constructor()
      keys = keys || Object.keys(obj)
      for (let k of keys)
        if (obj.hasOwnProperty(k))
          copy[k] = deep_copy(obj[k], keys)
      return copy
    }