Script Valley
Regex: Actually Useful Patterns
Quantifiers and Greedy vs Lazy MatchingLesson 4.1

Greedy quantifiers and why they over-match

greedy default behavior, star plus greedy, over-matching HTML, match expansion, how greedy backtrack works

Greedy Means Take As Much As Possible

Greedy matching

All quantifiers (* + {n,m}) are greedy by default: they match as many characters as possible while still allowing the overall pattern to succeed.

// Greedy: matches from first < to LAST >
'<b>bold</b> and <i>italic</i>'.match(/<.+>/)
// => ['<b>bold</b> and <i>italic</i>']

Greediness is correct when you want the longest match. It causes bugs when you expect to match the shortest balanced construct.

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Lazy quantifiers in regex with question mark suffix

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Greedy quantifiers and why they over-match — Quantifiers and Greedy vs Lazy Matching — Regex: Actually Useful Patterns — Script Valley — Script Valley