JSON quiz

Test your JSON knowledge with a free interactive quiz — 22 questions with answers and explanations. No signup needed to play.

How must object keys be written in JSON?

1. How must object keys be written in JSON?
2. A JavaScript `Date` object is passed to `JSON.stringify`. What appears in the output?
3. What is the `reviver` function in `JSON.parse(text, reviver)` used for?
4. What does it mean that JSON is "language-independent"?
5. What does `JSON.stringify(value)` do in JavaScript?
6. Can JSON represent a top-level array, like `[1, 2, 3]`?
7. Which of these is NOT a valid JSON value type?
8. What happens to a property whose value is `undefined` when you call `JSON.stringify`?
9. How are special characters like a double quote or newline represented inside a JSON string?
10. Which values are NOT valid JSON numbers?
11. What is the second argument to `JSON.stringify(value, replacer, space)` — the `space` parameter — used for?
12. What does JSON stand for?

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