why is my array deleting, js code example

Example 1: how to delete an element from an array

var array = [123, "yee", true];
array.pop(index);

Example 2: delete an item from array javascript

let items = [12, 548 ,'a' , 2 , 5478 , 'foo' , 8852, , 'Doe' ,2154 , 119 ]; 
items.length; // return 11 
items.splice(3,1) ; 
items.length; // return 10 
/* items will be equal to [12, 548, "a", 5478, "foo", 8852, undefined × 1, "Doe", 2154,       119]   */