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refactor(curriculum): JavaScript Objects Quiz (#58597)
This commit is contained in:
Estefania Cassingena Navone
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@ -17,7 +17,7 @@ To pass the quiz, you must correctly answer at least 18 of the 20 questions belo
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#### --text--
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Which of the following does not describe an object in JavaScript?
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Which of the following does NOT describe an object in JavaScript?
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#### --distractors--
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@ -29,11 +29,11 @@ A container for properties and methods.
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---
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One of JavaScript's data types.
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A non-primitive data type.
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#### --answer--
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One of JavaScript's primitives.
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A primitive data type.
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### --question--
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@ -43,58 +43,58 @@ Which of the following object definitions is invalid?
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#### --distractors--
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`const obj = { key: "some-value" }`
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`const book = { "pages": 255 };`
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---
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`const obj = { "some-value": key }`
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`const car = { year: 2025 };`
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---
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`const obj = { key: () => "some-value" }`
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`const person = { "name": "nora" };`
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#### --answer--
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`const obj = { key(): "some-value" }`
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`const product = { color: blue };`
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### --question--
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#### --text--
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Which of the following correctly accesses the value of the `key` property in the object below:
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How can you access the `job` property of this `person` object?
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```js
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const obj = { key: "some-value" }
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let person = { job: "Software Developer" };
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```
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#### --distractors--
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`obj -> key`
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`person -> job`
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---
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`obj#key`
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`person#job`
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---
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`obj[key]`
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`person[job]`
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#### --answer--
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`obj.key`
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`person.job`
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### --question--
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#### --text--
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Which of the following correctly accesses the value of the `street` property in the object below?
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How can you access the `street` property of the `person` object below?
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```js
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const person = {
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address: {
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street: "sample-street"
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}
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}
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};
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```
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#### --distractors--
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@ -117,7 +117,7 @@ const person = {
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#### --text--
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Which of the following property keys can only be used with a bracket notation as opposed to dot notation?
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Which of these property keys can only be accessed using bracket notation?
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#### --distractors--
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@ -125,7 +125,7 @@ A property key that is known and static.
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---
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A property key nested in multiple levels of the object.
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A property key that is nested within multiple levels of an object.
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---
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@ -139,7 +139,7 @@ A property key that is dynamic.
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#### --text--
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Which of the following correctly accesses the value of `name` property via destructuring in the object below?
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Which of the following correctly uses destructuring to access the `name` property of the `person` object below?
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```js
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const person = { name: "John" }
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@ -147,219 +147,222 @@ const person = { name: "John" }
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#### --distractors--
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`const name = person.name`
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`const name = person.name;`
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---
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`const name = person["name"]`
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`const name = person["name"];`
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---
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`const { ...name } = person`
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`const { ...name } = person;`
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#### --answer--
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`const { name } = person`
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`const { name } = person;`
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### --question--
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#### --text--
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Which of the following correctly accesses the value of `street` property via destructuring in the object below?
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Which of the following correctly uses destructuring to access the `flour` property of the `recipe` object below?
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```js
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const person = {
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address: {
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street: "sample-street"
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const recipe = {
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ingredients: {
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flour: "2 cups",
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sugar: "1 cup"
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}
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}
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};
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```
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#### --distractors--
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`const name = person.address.street`
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`const flour = recipe.ingredients.flour;`
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---
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`const name = person["address"]["street"]`
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`const flour = recipe["ingredients"]["flour"];`
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---
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`const { address: street } = person`
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`const { ingredients: flour } = recipe;`
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#### --answer--
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`const { address: { street } } = person`
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`const { ingredients: { flour } } = recipe;`
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### --question--
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#### --text--
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How do you assign a default value of `"defaultValue"` to a property key accessed via destructuring?
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How can you assign a default value to a property key when using destructuring in JavaScript?
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#### --distractors--
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`const key = object.key && "defaultValue"`
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`const key = object.key && "defaultValue";`
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---
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`const key = object.key || "defaultValue"`
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`const key = object.key || "defaultValue";`
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---
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`const { key: "defaultValue" } = object `
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`const { key: "defaultValue" } = object;`
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#### --answer--
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`const { key = "defaultValue" } = object`
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`const { key = "defaultValue" } = object;`
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### --question--
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#### --text--
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Which of the following objects does not inherit from `Object.prototype`?
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How can you check if a `car` object has a `year` property?
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#### --distractors--
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`const obj = Object.create(undefined)`
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`year.hasProperty("car");`
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---
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`const obj = new Object(null)`
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`car.hasProperty("year");`
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---
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`const obj = { proto: undefined }`
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`car.hasOwnProperty(year);`
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#### --answer--
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`const obj = Object.create(null}`
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`car.hasOwnProperty("year");`
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### --question--
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#### --text--
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Which of the following cannot be an object prototype?
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What is an object method?
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#### --distractors--
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`Math`
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A string associated with an object.
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---
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`Date`
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An array associated with an object.
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---
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`null`
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A number associated with an object.
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#### --answer--
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`undefined`
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A function associated with an object.
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### --question--
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#### --text--
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Which of the following correctly creates an object with the prototype below:
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How can you call the `add` method of this `calculator` object to add the numbers `10` and `7`?
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```js
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const samplePrototype = {
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doSomething: () => {}
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}
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const calculator = {
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add: function(a, b) {
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return a + b;
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}
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};
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```
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#### --distractors--
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`const obj = { proto: samplePrototype }`
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`calculator#add(10, 7);`
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---
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`const obj = { prototype: samplePrototype }`
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`calculator.call(add(10, 7));`
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---
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`const obj = new Object(samplePrototype)`
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`add.calculator(10, 7);`
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#### --answer--
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`const obj = Object.create(samplePrototype)`
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`calculator.add(10, 7);`
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### --question--
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#### --text--
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Which of the following keywords is used to identify a getter in an Object?
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Which operator removes a property from an object?
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#### --distractors--
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`getter`
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`remove`
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---
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`get_`
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`erase`
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---
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`_get`
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`discard`
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#### --answer--
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`get`
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`delete`
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### --question--
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#### --text--
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Which of the following keywords is used to identify a setter in an Object?
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How can you check if a `score` property exists in a `player` object?
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#### --distractors--
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`setter`
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`player in "score"`
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---
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`set_`
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`player in score`
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---
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`_set`
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`score in player`
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#### --answer--
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`set`
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`"score" in player`
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### --question--
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#### --text--
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Which of the following is true about object setters?
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How can you create a new empty object in JavaScript?
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#### --distractors--
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An object setter must be called with a parenthesis.
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`object() new`
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---
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An object setter must be defined with the same name as the property it sets.
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`new object()`
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---
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An object setter must be accompanied by a getter.
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`Object() new`
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#### --answer--
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An object setter must be defined with exactly one argument.
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`new Object()`
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### --question--
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#### --text--
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Which of the following is the correct syntax for optional chaining?
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What is the correct syntax for using optional chaining in JavaScript?
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#### --distractors--
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`object.key`
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`object?key`
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---
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@ -377,109 +380,123 @@ Which of the following is the correct syntax for optional chaining?
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#### --text--
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What is the difference between enumerable and non-enumerable properties in an object?
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What is optional chaining used for in JavaScript?
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#### --distractors--
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Enumerable properties are owned by the object while non-enumerable properties are not.
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Used to define variables with default values.
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---
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Enumerable properties are defined by the object while non-enumerable properties can only be inherited.
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Used to define optional methods within an object that may or may not be called.
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---
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Enumerable properties can be accessed via dot notation while non-enumerable properties can only be accessed via bracket notation.
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Used to write more concise code by chaining multiple method calls together in a single statement.
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#### --answer--
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Enumerable properties are properties whose internal enumerable flag is set to true while non-enumerable properties' internal enumerable flag is set to false.
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Used to safely access properties of an object that might be `null` or `undefined`.
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### --question--
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#### --text--
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What is the difference between `Object.keys()` and `Object.getOwnPropertyNames()`?
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What method is used to convert a JavaScript object into a JSON string?
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#### --distractors--
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`Object.keys()` returns all the properties prefixed with the word `key_` while `Object.getOwnPropertyNames()` returns all object properties regardless of prefix.
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`Stringify.toJSON()`
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---
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`Object.keys()` returns all properties inherited and owned by the object while `Object.getOwnPropertyNames()` only returns properties owned by the object.
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`JSON.toObject()`
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---
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`Object.keys()` and `Object.getOwnPropertyNames()` will always return the same list of properties.
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`Object.toJSON()`
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#### --answer--
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`Object.keys()` returns only enumerable properties of an object while `Object.getOwnPropertyNames()` returns enumerable and non-enumerable properties except for those which use Symbol.
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`JSON.stringify()`
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### --question--
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#### --text--
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Which of the following is true for an object sealed with `Object.seal`?
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What method converts a JSON string back into a JavaScript object?
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#### --distractors--
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Values of existing properties cannot be changed.
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`JSON.toObject()`
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---
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Values of existing properties can be changed but doing this will unseal the object.
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`JSON.convert()`
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---
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New properties can be added but existing properties can not be removed.
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`JSON.object()`
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#### --answer--
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New properties cannot be added and existing properties cannot be removed.
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`JSON.parse()`
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### --question--
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#### --text--
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Which of the following is true for an object frozen with `Object.freeze`?
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Which one of these options accesses the `color` property of a `toy` object using bracket notation?
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#### --distractors--
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New properties can be added but existing properties can not be removed.
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`toy.color`
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---
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New properties can be added but doing this will unfreeze the object.
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`toy[color]`
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---
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Values of existing properties can be changed but doing this will unfreeze the object.
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`color[toy]`
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#### --answer--
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Values of existing properties cannot be changed.
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`toy["color"]`
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### --question--
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#### --text--
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What is the right way to completely remove a property from an object?
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How can you access the `home` phone of this `learner` object in JavaScript using dot notation?
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```js
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const learner = {
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name: "Nora",
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age: 45,
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contact: {
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email: "nora@email.com",
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phone: {
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home: "123-456-7890",
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work: "098-765-4321"
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}
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}
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};
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```
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#### --distractors--
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`Object.delete(object, propertyKey)`
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`learner.name.phone.home`
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---
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`remove object.propertyKey`
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`learner.email.work`
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---
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`object.propertyKey = undefined`
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`learner.contact.home`
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#### --answer--
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`delete object.propertyKey`
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`learner.contact.phone.home`
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Block a user