JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr=[1234, 1245, 48956, 96448, 35780];
		//var arr=[96448, 35780];		  
		  var diff=[];
		  $.each(arr,function(i,v){
		   //96448 - 35780 = 60668 / 96448 = 0,629 * 100 = 62,9%
		   if(i==arr.length-1){
			diff.push('---');
			return;
		   }
		   var first=v;
		   var second=arr[i+1];
		     var calc =(((first - second)/first)*100).toFixed(2)+'%';
			 diff.push(calc);
		  });
		  alert(diff.toString());