JSFiddle - React, Tailwind, and code Playground

JavaScript

var array = [4, 10, 20, 30, 50, 67, 4, 20];
var len = array.length;
var high = 0;

for (i = 0; i < len || function(){ alert(high); return false;}(); i += 2){
    
    largest_diff(array[i], array[i+1]);
    
        
}

function largest_diff(x, y){
    
    var sum = x - y;
    
    var absolute = Math.abs(sum);
        
    if(absolute > high){
           high = absolute;
    }
    
    return high;
}