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JavaScript JSON — exercises and bug fixes

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

    Turn an object into text

    easy10 min

    Stringify a person object and show the text.

  2. 2

    Turn text into an object

    easy10 min

    Parse a JSON string and show the name from it.

  3. 3

    Round trip an object

    easy10 min

    Stringify then parse an object and show the year.

  4. 4

    Make a deep copy

    easy10 min

    Copy a nested object through JSON, change the copy, and show the original city.

  5. 5

    Handle invalid JSON

    medium10 min

    Wrap a parse in a try block and report when the text is not valid.

Find the bug(5)

  1. 1

    Fix parse used instead of stringify

    easy8 min

    An object needs turning into text, not the other way round.

  2. 2

    Fix the text used without parsing

    easy8 min

    A JSON string has no properties until it is parsed.

  3. 3

    Fix the shallow copy

    easy8 min

    Spread shares the nested object, so the original was changed too.

  4. 4

    Fix the unguarded parse

    easy8 min

    Invalid text throws, so the parse needs a try block.

  5. 5

    Fix the single quotes in the JSON

    easy8 min

    JSON requires double quotes around every key and string.

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