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JavaScript Regex Groups — exercises and bug fixes

5 hands-on exercises and 5 find-the-bug challenges for the JavaScript Regex Groups lesson. Every one is checked automatically in the browser — write the code, run it, and the tests tell you what still fails.

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Exercises(5)

  1. 1

    Capture the year

    easy10 min

    Pull the year out of the date with a group.

  2. 2

    Use a named group

    easy10 min

    Name the group and read it from groups.

  3. 3

    Repeat a group

    easy10 min

    Check the text is the pair ab repeated.

  4. 4

    Match one of two words

    easy10 min

    Accept only cat or dog.

  5. 5

    Rearrange with groups

    medium10 min

    Turn the ISO date into the British order.

Find the bug(5)

  1. 1

    Fix the whole match used as a group

    easy8 min

    Position 0 is the full match; the groups start at 1.

  2. 2

    Fix the replacement references

    easy8 min

    The parts are in the wrong order for a British date.

  3. 3

    Fix the alternation without brackets

    easy8 min

    Without brackets the anchors apply to only one alternative.

  4. 4

    Fix the quantifier on one character

    easy8 min

    The quantifier should repeat the whole pair, not just the b.

  5. 5

    Fix the named group read by number

    easy8 min

    A named group is read through groups, by its name.

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