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JavaScript Object keys and values — exercises and bug fixes

5 hands-on exercises and 5 find-the-bug challenges for the JavaScript Object keys and values 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

    List the keys

    easy10 min

    Show the property names joined by commas.

  2. 2

    List the values

    easy10 min

    Show the property values joined by commas.

  3. 3

    Count the properties

    easy10 min

    Show how many properties an object has.

  4. 4

    Total the values

    easy10 min

    Add up every value in a scores object.

  5. 5

    Loop over entries

    medium10 min

    Build a string of each key and value, separated by spaces.

Find the bug(5)

  1. 1

    Fix length used on an object

    easy8 min

    Objects have no length property.

  2. 2

    Fix keys used instead of values

    easy8 min

    The names are being totalled, not the numbers.

  3. 3

    Fix the method called on the object

    easy8 min

    These are functions on Object, not methods of your object.

  4. 4

    Fix entries not unpacked

    easy8 min

    Each entry is a pair, so it needs destructuring.

  5. 5

    Fix values used instead of keys

    easy8 min

    The property names are wanted, not the numbers.

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