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Regex literals use /pattern/flags:

Flags: i (case-insensitive), g (all matches, not just the first), m (multiline ^/$), s (dot matches newline), u (unicode-aware).

Key patterns:

• \d digit, \w word char, \s whitespace
• ^ start of line/string, $ end
• . any char (except newline by default)
• * zero or more, + one or more, ? zero or one
• (...) capture group, (?:...) non-capturing
• [abc] character class, [^abc] negated

For capture groups, use .match() (single match) or .matchAll() (iterator over all matches).