JS.09.01 Junior

Regex basics

Comes up in: JavaScript, Coding

This concept is being written. It gets the full five steps — explanation, predict, interview angle, practice with tests, and review cards. Here is exactly what it will cover, so you can study it elsewhere in the meantime.

What it covers

literals vs RegExp
character classes
quantifiers (greedy/lazy)
anchors
groups and alternation
flags g i m s u v y d
test, match, matchAll, replace with functions

Words you will know

regular expressionquantifieranchorcapture groupflag

What you will practise

10 small patterns with tests

Interview questions this answers

What is the difference between greedy and lazy quantifiers?
Why does calling test twice on a global regex give different results?
Write a regex to validate an Indian PIN code / a hex colour.