deep-clone.js

/**
 * Clones an object and all sub-objects.
 * `into = from;` -> `into = deepClone(from);` | `deepClone(from, into);`
 * @param  {Object}  from                  Getter object.
 * @param  {Object}  [into = {}]           Setter object.
 * @param  {boolean} [noOverwrite = false] Flag to not overwrite non-null values in `into` if true.
 * @return {Object}                        Returns `into`.
 */
export default function deepClone(from, into = {}, noOverwrite = false) {
  let into = this == global ? Object.create(Object.getPrototypeOf(from)) : this;
  for (let k of Object.keys(from)) {
    if (from[k] && typeof from[k] === 'object') {
      if (into[k] && typeof into[k] === 'object') {
        deepClone(from[k], into[k]);
      } else if (!noOverwrite || into[k] == null) {
        into[k] = deepClone(from[k]);
      }
    } else if (!noOverwrite || into[k] == null) {
      into[k] = from[k];
    }
  }
  return into;
}