Regex Practice 5/8

Groups and capture

Parentheses (...) group part of a pattern - and also capture what matched there, so you can pull it back out. str.match(/Hello, (\w+)!/) returns an array where [0] is the whole match and [1] is whatever the first group captured.

Naming a group makes this easier to read: (?<year>\d{4}) captures the same thing but stores it under match.groups.year instead of a numbered index. This is how you turn "did it match" into "here's the piece I actually wanted."

Your task: write capturedName(str), returning the name captured from a greeting shaped like "Hello, Ada!" (or null if it doesn't match), and parseDate(dateStr), returning { year, month, day } (each a string) parsed from a date shaped like "2026-07-10" using named groups (or null if it doesn't match).

You'll practice:

Capturing part of a match with (...) and reading it from the match array
Naming a group with (?<name>...) and reading match.groups.name

// Write capturedName(str): the name in "Hello, <name>!", or null.
function capturedName(str) {

}

// Write parseDate(dateStr): { year, month, day } from "YYYY-MM-DD", or null.
function parseDate(dateStr) {

}