JSFiddle - React, Tailwind, and code Playground

HTML

<script type="application/javascript;version=1.7">
    function test() {

        for (let i = 0; i < 10; i++) {

            alert(i); // 1, 2, 3, 4 ... 9
        }

        alert(i); // i is not defined
    }
</script>

JavaScript

test();