findRestaurantById.js

// restaurants are loaded...
var restaurants = [
  {
    "id": 324,
    "name": "Tien Hiang",
  },
  {
    "id": 329,
    "name": "Hank Burger",
  },
  …
];

/*
 * Finds a restaurant by its given ID.
 *
 * @param restaurantId The restaurant identifier to lookup.
 * @return Returns a restaurant object or null.
 */
var findRestaurantById(restaurantId) {
  for (var i = 0; i < restaurants.length; i++) {
    if (restaurants[i] === restaurantId) {
      return restaurants[i];
    }
  }
}