Regex is a superpower that most developers fear. Let me demystify it with practical patterns you'll use daily.
Essential Syntax
Practical Patterns
Named Groups
Lookahead and Lookbehind
Performance Tips
- Avoid catastrophic backtracking:
/(a+)+$/is O(2^n) on non-matching strings - Use non-greedy quantifiers (
*?,+?) when possible - Anchor patterns with
^and$ - Cache compiled RegExp objects — don't create new ones in loops
- Use
String.includes()instead of regex for simple substring checks