JSFiddle - React, Tailwind, and code Playground

JavaScript

var l = /[a-z]/g;

// will match "a" and return true
console.log(l.test("a"));
// lastIndex is now 1
console.log(l.lastIndex);

// starts searching from position 1, and doesn't match anything
// so returns false
console.log(l.test("x---"));
// wraps around lastIndex is now 0 again, should behave normally now
console.log(l.lastIndex);