JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = [1, 80, 2000];
generateProportion(a);
function generateProportion(arr){
    var total = 0;
     for(var k=0;k <arr.length;k++)
         total += arr[k];
    
    var newArr = new Array();
    for(var i=0;i< arr.length; i++)
    {
        newArr.push((arr[i]/total).toFixed(2));
    }
    alert(newArr);
    
}