JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = [5, 5, 5, 2, 2, 2, 2, 2, 9, 4, 5, 5, 5];

function identical(array){
   
    var newArray=[];
    newArray.push(arr[0]);
    var count = 0;
    for(var i = 0; i < array.length -1; i++){
        if(array[i] != array[i + 1]){
            newArray.push(array[i + 1]);
        }
    }
    console.log(newArray);
}
identical(arr);