chore: import upstream snapshot with attribution

curriculum/challenges/english/blocks/quiz-javascript-objects/66edcd0ecb4b25dc64a34804.md

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+---
+id: 66edcd0ecb4b25dc64a34804
+title: JavaScript Objects Quiz
+challengeType: 8
+dashedName: quiz-javascript-objects
+---
+
+# --description--
+
+To pass the quiz, you must correctly answer at least 18 of the 20 questions below.
+
+# --quizzes--
+
+## --quiz--
+
+### --question--
+
+#### --text--
+
+Which of the following does NOT describe an object in JavaScript?
+
+#### --distractors--
+
+A collection of key-value pairs.
+
+---
+
+A container for properties and methods.
+
+---
+
+A non-primitive data type.
+
+#### --answer--
+
+A primitive data type.
+
+### --question--
+
+#### --text--
+
+Which of the following object definitions is invalid?
+
+#### --distractors--
+
+`const book = { "pages": 255 };`
+
+---
+
+`const car = { year: 2025 };`
+
+---
+
+`const person = { "name": "nora" };`
+
+#### --answer--
+
+`const product = { color: blue };`
+
+### --question--
+
+#### --text--
+
+How can you access the `job` property of this `person` object?
+
+```js
+let person = { job: "Software Developer" };
+```
+
+#### --distractors--
+
+`person -> job`
+
+---
+
+`person#job`
+
+---
+
+`person[job]`
+
+#### --answer--
+
+`person.job`
+
+### --question--
+
+#### --text--
+
+How can you access the `street` property of the `person` object below?
+
+```js
+const person = {
+  address: {
+    street: "sample-street"
+  }
+};
+```
+
+#### --distractors--
+
+`person -> address -> street`
+
+---
+
+`person#address#street`
+
+---
+
+`person[address.street]`
+
+#### --answer--
+
+`person["address"]["street"]`
+
+### --question--
+
+#### --text--
+
+Which of these property keys can only be accessed using bracket notation?
+
+#### --distractors--
+
+A property key that is known and static.
+
+---
+
+A property key that is nested within multiple levels of an object.
+
+---
+
+A property key that might not exist in the object.
+
+#### --answer--
+
+A property key that is dynamic.
+
+### --question--
+
+#### --text--
+
+Which of the following correctly uses destructuring to access the `name` property of the `person` object below?
+
+```js
+const person = { name: "John" }
+```
+
+#### --distractors--
+
+`const name = person.name;`
+
+---
+
+`const name = person["name"];`
+
+---
+
+`const { ...name } = person;`
+
+#### --answer--
+
+`const { name } = person;`
+
+### --question--
+
+#### --text--
+
+Which of the following correctly uses destructuring to access the `flour` property of the `recipe` object below?
+
+```js
+const recipe = {
+  ingredients: {
+    flour: "2 cups",
+    sugar: "1 cup"
+  }
+};
+```
+
+#### --distractors--
+
+`const flour = recipe.ingredients.flour;`
+
+---
+
+`const flour = recipe["ingredients"]["flour"];`
+
+---
+
+`const { ingredients: flour } = recipe;`
+
+#### --answer--
+
+`const { ingredients: { flour } } = recipe;`
+
+### --question--
+
+#### --text--
+
+How can you assign a default value to a property key when using destructuring in JavaScript?
+
+#### --distractors--
+
+`const key = object.key && "defaultValue";`
+
+---
+
+`const key = object.key || "defaultValue";`
+
+---
+
+`const { key: "defaultValue" } = object;`
+
+#### --answer--
+
+`const { key = "defaultValue" } = object;`
+
+### --question--
+
+#### --text--
+
+How can you check if a `car` object has a `year` property?
+
+#### --distractors--
+
+`year.hasProperty("car");`
+
+---
+
+`car.hasProperty("year");`
+
+---
+
+`car.hasOwnProperty(year);`
+
+#### --answer--
+
+`car.hasOwnProperty("year");`
+
+### --question--
+
+#### --text--
+
+What is an object method?
+
+#### --distractors--
+
+A string associated with an object.
+
+---
+
+An array associated with an object.
+
+---
+
+A number associated with an object.
+
+#### --answer--
+
+A function associated with an object.
+
+### --question--
+
+#### --text--
+
+How can you call the `add` method of this `calculator` object to add the numbers `10` and `7`?
+
+```js
+const calculator = {
+  add: function(a, b) {
+    return a + b;
+  }
+};
+```
+
+#### --distractors--
+
+`calculator#add(10, 7);`
+
+---
+
+`calculator.call(add(10, 7));`
+
+---
+
+`add.calculator(10, 7);`
+
+#### --answer--
+
+`calculator.add(10, 7);`
+
+### --question--
+
+#### --text--
+
+Which operator removes a property from an object?
+
+#### --distractors--
+
+`remove`
+
+---
+
+`erase`
+
+---
+
+`discard`
+
+#### --answer--
+
+`delete`
+
+### --question--
+
+#### --text--
+
+How can you check if a `score` property exists in a `player` object?
+
+#### --distractors--
+
+`player in "score"`
+
+---
+
+`player in score`
+
+---
+
+`score in player`
+
+#### --answer--
+
+`"score" in player`
+
+### --question--
+
+#### --text--
+
+How can you create a new empty object in JavaScript?
+
+#### --distractors--
+
+`object() new`
+
+---
+
+`new object()`
+
+---
+
+`Object() new`
+
+#### --answer--
+
+`new Object()`
+
+### --question--
+
+#### --text--
+
+What is the correct syntax for using optional chaining in JavaScript?
+
+#### --distractors--
+
+`object?key`
+
+---
+
+`object.["key"]`
+
+---
+
+`object.?key`
+
+#### --answer--
+
+`object?.key`
+
+### --question--
+
+#### --text--
+
+What is optional chaining used for in JavaScript?
+
+#### --distractors--
+
+Used to define variables with default values.
+
+---
+
+Used to define optional methods within an object that may or may not be called.
+
+---
+
+Used to write more concise code by chaining multiple method calls together in a single statement.
+
+#### --answer--
+
+Used to safely access properties of an object that might be `null` or `undefined`.
+
+### --question--
+
+#### --text--
+
+What method is used to convert a JavaScript object into a JSON string?
+
+#### --distractors--
+
+`Stringify.toJSON()`
+
+---
+
+`JSON.toObject()`
+
+---
+
+`Object.toJSON()`
+
+#### --answer--
+
+`JSON.stringify()`
+
+### --question--
+
+#### --text--
+
+What method converts a JSON string back into a JavaScript object?
+
+#### --distractors--
+
+`JSON.toObject()`
+
+---
+
+`JSON.convert()`
+
+---
+
+`JSON.object()`
+
+#### --answer--
+
+`JSON.parse()`
+
+### --question--
+
+#### --text--
+
+Which one of these options accesses the `color` property of a `toy` object using bracket notation?
+
+#### --distractors--
+
+`toy.color`
+
+---
+
+`toy[color]`
+
+---
+
+`color[toy]`
+
+#### --answer--
+
+`toy["color"]`
+
+### --question--
+
+#### --text--
+
+How can you access the `home` phone of this `learner` object in JavaScript using dot notation?
+
+```js
+const learner = {
+  name: "Nora",
+  age: 45,
+  contact: {
+    email: "nora@email.com",
+    phone: {
+      home: "123-456-7890",
+      work: "098-765-4321"
+    }
+  }
+};
+```
+
+#### --distractors--
+
+`learner.name.phone.home`
+
+---
+
+`learner.email.work`
+
+---
+
+`learner.contact.home`
+
+#### --answer--
+
+`learner.contact.phone.home`
+