JSFiddle - React, Tailwind, and code Playground

JavaScript

// create an array with 1 million objects in it
var arr = [];
for(var i=0; i< 1000000; i++)
{
    arr.push({id:i, name:'obj'+i});
}

// cache the length
var arrLen = arr.length;

// TEST 1: get the array length 1 billion times (1000 million)
var start = new Date();
for(var j=0; j < 1000000000; j++)
{
    var k = arr.length;
}
var end = new Date();
console.log("length test", end - start)

// TEST 2: get the cached array length 1 billion times 
var start2 = new Date();
for(var j2=0; j2 < 1000000000; j2++)
{
    var k2 = arrLen;
}
var end2 = new Date();
console.log("cached length", end2 - start2)