Function add

third_party/closure/goog/object/object.js:335–340

* Adds a key-value pair to the object. Throws an exception if the key is * already in use. Use set if you want to change an existing pair. * @param {?Object } obj The object to which to add the key-value pair. * @param {string} key The key to add. * @param {V} val The value to add. * @retur

(obj, key, val)

 * @template K,V
 */
function add(obj, key, val) {
  if (obj !== null && key in obj) {
    throw new Error(`The object already contains the key "${key}"`);
  }
  set(obj, key, val);
}

/**
 * Returns the value for the given key.