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Strings · medium

30. Advanced Regex & Named Capture Groups

Assertions, lookaheads, and named capture groups.

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Modern regexes support named capture groups (`(?<name>pattern)`) and lookaround assertions (`(?<=...)`, `(?=...)`) for parsing text cleanly.

js
const match = "0xAbC...".match(/^0x(?<hex>[a-fA-F0-9]+)$/);
console.log(match?.groups?.hex);

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  2. 2. Re-read the code snippets and say out loud what each line does.
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Check your understanding

  1. 1. How do you define a named capture group in JavaScript regex?

  2. 2. What does a positive lookahead (?=...) do?

  3. 3. Why is the global regex flag /g with RegExp.test() risky in loops?

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