javascript get first or undefined code example

Example 1: js get first item from array

var colors = ["red", "green", "blue"];
var red=colors.shift();
//colors is now ["green","blue"];

Example 2: javascript get first element of array

let mylist = ['one','two','three','last'];
mylist[0],mylist[1],mylist[2],mylist[3];//this is called indexing and slicing in python
//in javascript it called getting elements in array