Real Life Objects, Properties, and Methods Mockest | JavaScript

11.

How do you define a method in a constructor function?

A). this.methodName = function() {} B). this.methodName: function() {} C). this.methodName = () {} D). this.methodName: () {}

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12.

What does Object.keys(obj) return?

A). An array of the values of the object's properties B). An array of the names of the object's properties C). The first key of the object D). The number of properties in the object

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13.

How can you check if a property exists in an object?

A). 'property' in object B). object.hasProperty('property') C). object.contains('property') D). object.includes('property')

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14.

Which of the following is the correct way to delete a property from an object?

A). remove object.property; B). delete object.property; C). delete object[property]; D). object.property = null;

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15.

What will car['make'] return if var car = {make: 'Ford', model: 'Mustang'};?

A). Ford B). Mustang C). Undefined D). Error

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16.

How can you iterate over all properties of an object?

A). for (var key of object) B). for (var key in object) C). for (var key with object) D). for (var key over object)

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17.

What does Object.assign(target, ...sources) do?

A). Copies properties from sources to target B). Compares properties between target and sources C). Deletes properties in sources D). Merges properties of sources into target and removes duplicates

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18.

How do you define a class in JavaScript ES6?

A). class ClassName { constructor() {} } B). function ClassName() { constructor() {} } C). class ClassName() { constructor {} } D). function class ClassName { constructor() {} }

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19.

How do you define a method inside a class in JavaScript ES6?

A). methodName() {} B). this.methodName = function() {} C). function methodName() {} D). methodName: function() {}

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20.

What is encapsulation in the context of JavaScript objects?

A). Hiding the internal state and requiring all interaction to be performed through an object's methods B). Extending one object from another C). Creating a new object D). Removing a property from an object

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