JSFiddle - React, Tailwind, and code Playground

JavaScript

var i = 10;

function outer() {
    alert(i); // 10
    var i = 5;
    alert(i); // 5
    function inner() {
        var i = 20;
    }
    inner();
    alert(i); // 5
    if (1) {
        var i = 30;
    }
    alert(i); // 5
    setTimout(function () {
        alert(i); // 5
    }, 100);
}

outer();