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JavaScript Arrays — exercises and bug fixes

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

    Create an array

    easy10 min

    Create an array of three fruit names and show how many it holds.

  2. 2

    Show an empty array length

    easy10 min

    Create an empty array and show its length.

  3. 3

    Store mixed types

    easy10 min

    Create an array holding a string, a number and a boolean, then show the type of the middle element.

  4. 4

    Count a nested row

    medium10 min

    Create a grid of two rows with three values each and show the length of the first row.

  5. 5

    Grow a const array

    easy10 min

    Push a value onto an array declared with const and show the new length.

Find the bug(5)

  1. 1

    Fix the missing commas

    easy8 min

    The array was written without separators, so it holds one value instead of three.

  2. 2

    Fix the wrong brackets

    easy8 min

    Curly braces make an object, not an array, so there is no length.

  3. 3

    Fix length called as a function

    easy8 min

    length is a property, not a method.

  4. 4

    Fix the flat grid

    easy8 min

    The grid should hold rows, but every value was put in one list.

  5. 5

    Fix the array that was replaced

    easy8 min

    Building a new array loses the earlier values instead of adding to them.

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