Function assignMergeValue

lodash.js:2501–2506

* This function is like `assignValue` except that it doesn't assign * `undefined` values. * * @private * @param {Object} object The object to modify. * @param {string} key The key of the property to assign. * @param {*} value The value to assign.

(object, key, value)

     * @param {*} value The value to assign.
     */
    function assignMergeValue(object, key, value) {
      if ((value !== undefined && !eq(object[key], value)) ||
          (value === undefined && !(key in object))) {
        baseAssignValue(object, key, value);
      }
    }

    /**
     * Assigns `value` to `key` of `object` if the existing value is not equivalent