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JavaScript Class Methods — exercises and bug fixes

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

    Write a method with a parameter

    easy10 min

    Add a deposit method that increases the balance and returns it.

  2. 2

    Call another method

    easy10 min

    Have total call tax through this.

  3. 3

    Show methods are shared

    easy10 min

    Report whether two instances share the same method function.

  4. 4

    Chain method calls

    easy10 min

    Return this from up so the calls can be chained.

  5. 5

    Bind a detached method

    medium10 min

    Pull the method out and bind it so it still works.

Find the bug(5)

  1. 1

    Fix the method with no return

    easy8 min

    The method works out the answer but never gives it back.

  2. 2

    Fix the sibling method called without this

    easy8 min

    A method must be reached through this.

  3. 3

    Fix the chain that returns a value

    easy8 min

    up must return this for chaining to work.

  4. 4

    Fix the detached method

    easy8 min

    Taking a method out of its object loses this.

  5. 5

    Fix the method defined in the constructor

    easy8 min

    A method belongs in the class body so instances share it.

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