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JavaScript Debugging — exercises and bug fixes

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

    Check the types

    easy10 min

    Report the types of a string and a number.

  2. 2

    Spot the type mismatch

    easy10 min

    Report whether the two values are strictly equal.

  3. 3

    Label what you print

    easy10 min

    Build a labelled report of the width and area.

  4. 4

    Narrow down a pipeline

    easy10 min

    Report the value after each stage of the transformation.

  5. 5

    Find the wrong assumption

    medium10 min

    Convert the value before adding, and report the total.

Find the bug(5)

  1. 1

    Fix the values compared without checking types

    easy8 min

    The two look identical when printed but are different types.

  2. 2

    Fix the unlabelled output

    easy8 min

    Bare values give no clue which is which.

  3. 3

    Fix the silent joining bug

    easy8 min

    The price is text, so plus joins instead of adding.

  4. 4

    Fix the wrong filter boundary

    easy8 min

    The pipeline keeps the wrong values, which printing each stage reveals.

  5. 5

    Fix the type read from the value

    easy8 min

    Printing the value alone does not reveal its type.

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