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Reference

Regex cheat sheet

JavaScript regular expression syntax in one place: character classes, anchors, quantifiers, capture groups, lookaround assertions and the flags that change matching behaviour.

Classes

Anchors

Quantifiers

Groups

Lookaround

Flags

JS API

Things worth remembering

  • Quantifiers are greedy by default. Add ? to make them lazy: .*? stops at the first match.
  • Named groups read better than indexes: str.match(re).groups.year.
  • Escape user input before building a RegExp, otherwise a stray ( throws a SyntaxError.

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