Name: JavaScript Regular Expressions: Quantifiers
Description: Quantifiers let you match repeating patterns without writing them out by hand.

Quantifiers let you match repeating patterns without writing them out by hand. This lesson covers the full spectrum: exact counts with {n}, ranges with {n,m}, and the three most common shorthand quantifiers — asterisk (*) for zero or more, plus (+) for one or more, and question mark (?) for zero or one. We also tackle the critical distinction between greedy and lazy quantifiers, showing how adding a question mark after any greedy quantifier makes it lazy.

app.js

import output from "./output.js";

// ─── Quantifiers — How Many ─────────────────────────────

const str = `aaaaaaa`;
const str = `color or colour`;
const str = `http://el337.com
not a web address
http://
https://www.el337.com`;
const str = `The "answer" was "perfect" again`;

let regex = /aaaa/g;
regex = /a{4}/g;
regex = /a{5}/g;
regex = /a{5,}/g;
regex = /a{5,6}/g;
regex = /a{0,}/g; // * (zero or more)
regex = /a*/g;
regex = /a{1,}/g; // + (one or more)
regex = /a+/g;
regex = /a{0,1}/g; //? (zero or one)
regex = /a?/g;
// update str.
regex = /colou?r/g;
regex = /https{0,1}/g;
regex = /https{0,1}:\/\/.{1,}/g;
regex = /https?:\/\/.+/g;
// add "more"
regex = /https?:\/\/.+\.com/g;
// change str
regex = /".+"/g;
regex = /".+?"/g;

output(str, regex);