Object Properties Mockest | JavaScript

1.

What is the correct way to create an object in JavaScript?

A). var obj = {}; B). var obj = []; C). var obj = (); D). var obj = <>;

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2.

How do you access the value of the name property in the object var person = {name: 'John', age: 30};?

A). person['name'] B). person.name C). person->name D). person::name

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3.

How do you add a new property gender with value male to the person object?

A). person.gender = 'male'; B). person.gender = male; C). person.gender = ['male']; D). person[gender] = 'male';

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4.

How can you delete the age property from the person object?

A). delete person.age; B). remove person.age; C). person.age = null; D). person.age.delete;

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5.

What will the following code output? console.log(person['age']); if var person = {name: 'John'};

A). 30 B). John C). undefined D). null

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6.

How do you define a method named greet in an object var person = {};?

A). person.greet = function() {}; B). person.greet: function() {}; C). person.greet = () {}; D). person.greet = function {};

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7.

What does Object.keys(person) return if var person = {name: 'John', age: 30};?

A). ['name', 'age'] B). ['John', 30] C). {'name', 'age'} D). {'John', 30}

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8.

How can you check if the age property exists in the person object?

A). 'age' in person B). person.has('age') C). person.contains('age') D). person.hasOwnProperty('age')

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9.

What will console.log(car.make); output if var car = {make: 'Toyota', model: 'Corolla'};?

A). Toyota B). Corolla C). Undefined D). Error

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10.

How do you iterate over all properties of an object var person = {name: 'John', age: 30};?

A). for (var key in person) B). for (var key of person) C). forEach(key in person) D). forEach(key of person)

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Object Properties Mocktest

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