By utilizing the push method, a new list is generated with its last element being '333'
If you use Console.log(list), you will see the detailed internal representation of the list. To avoid this verbosity, you can utilize either the last method or map.
var myList = Immutable.List([ 1, 2, 3 ]);
let updatedList = myList.push('333');
// display the last element
console.log(updatedList.last())
// display all elements
updatedList.map((element)=> console.log(element))
An alternative approach is to employ toJS() in order to convert the immutable array into a regular javascript array. This allows for easy printing of the array contents.