When to use it
- Use it to test whether a pattern matches text before writing code.
- It is useful for checking capture groups and match positions.
- It helps with validation, extraction, and search rules.
Types and modes
- g finds all matches in the text.
- i ignores letter case.
- m changes how ^ and $ work across multiple lines, and s lets dot match line breaks.
What to check
- Capture groups are values wrapped in parentheses.
- A broad pattern can match more than you expect.
- Flag combinations can change the result a lot.
FAQ
Flags, line breaks, or greedy matching may still prevent the expected result.
They let you extract or reuse specific parts of a match.
Matches
Matches3
[ "foo" ]
[ "bar" ]
[ "foo" ]
Matches include positions and capture groups when available.