(function(window) {
  function define_library() {
    // Create the library object and all its properties and methods.
    var vanillaZoom = {};
    vanillaZoom.init = function(galleryId) {
      // Our library's logic goes here.
    }
    return vanillaZoom;
  }

  // Add the vanillaZoom object to global scope if its not already defined.
  if(typeof(vanillaZoom) === 'undefined') {
    window.vanillaZoom = define_library();
  }
  else{
    console.log("Library already defined.");
  }
})(window);