JSFiddle - React, Tailwind, and code Playground

JavaScript

function count(obj) {
    "use strict";
    var i = 0;

    for (var props in obj) {
        i++;
    }

    return i;
}

var a = { a: 1, b: 2 };
console.log(count(a)); // 2
var b = function () {};
console.log(count(b)); // 0
var c = [1, 2, 3];
console.log(count(c)); // 3
var d = [];
d[100] = 1;
console.log(count(d)); // 1