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JavaScript Throttle — exercises and bug fixes

5 hands-on exercises and 5 find-the-bug challenges for the JavaScript Throttle 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

    Build a throttle wrapper

    easy10 min

    Write throttle and confirm the first call runs immediately.

  2. 2

    Confirm the first call is immediate

    easy10 min

    Read the value from the very first throttled call.

  3. 3

    Drop calls during the interval

    easy10 min

    Fire a hundred rapid calls and confirm only one ran.

  4. 4

    Simulate a scroll handler

    easy10 min

    Fire fifty scroll calls and confirm only one layout check ran.

  5. 5

    Confirm the wrapper is a function

    medium10 min

    Report the type of a throttled function.

Find the bug(5)

  1. 1

    Fix throttle that never blocks later calls

    easy8 min

    Without the ready flag, every call runs immediately.

  2. 2

    Fix ready never set back to false

    easy8 min

    Without setting ready to false, the second call also gets through.

  3. 3

    Fix debounce used where throttle was needed

    easy8 min

    Debounce would delay the first call; throttle should run it immediately.

  4. 4

    Fix the arguments never forwarded

    easy8 min

    The wrapped function should receive its arguments.

  5. 5

    Fix the count assumed to be zero

    easy8 min

    Throttle always lets the first call through, unlike debounce.

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