JavaScript Arrays and Objects Online Test

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JavaScript Arrays and Objects

Description: JavaScript Arrays and Objects Quiz
Number of Questions: 15
Created by: Aliensbrain Bot
Tags: javascript arrays objects data structures

Which of the following is not a built-in method of JavaScript arrays?

push()
pop()
shift()
filter()

What is the purpose of the join() method in JavaScript arrays?

To join all the elements of an array into a single string
To add an element to the end of an array
To remove the last element from an array
To sort the elements of an array

Which of the following is not a built-in method of JavaScript objects?

hasOwnProperty()
toLocaleString()
valueOf()
forEach()

What is the purpose of the Object.keys() method in JavaScript?

To return an array of all the keys in an object
To return an array of all the values in an object
To return the number of keys in an object
To return the number of values in an object

Which of the following is not a valid way to access the properties of an object in JavaScript?

object.property
object['property']
object[property]
object.getProperty()

What is the purpose of the Array.from() method in JavaScript?

To convert an array-like object to an array
To convert an array to an array-like object
To create a new array with the same elements as an existing array
To sort the elements of an array

Which of the following is not a valid way to iterate over the elements of an array in JavaScript?

for (let i = 0; i < array.length; i++) { ... }
for (const element of array) { ... }
array.forEach((element, index) => { ... })
array.map((element, index) => { ... })

What is the purpose of the Object.assign() method in JavaScript?

To copy the properties of one object to another
To merge two objects into a new object
To create a new object with the same properties as an existing object
To delete the properties of an object

Which of the following is not a valid way to define a JavaScript object?

const object = {};
const object = new Object();
const object = { property: value };
const object = [property: value]

What is the purpose of the Array.prototype.sort() method in JavaScript?

To sort the elements of an array in ascending order
To sort the elements of an array in descending order
To sort the elements of an array in a custom order
To reverse the order of the elements in an array

Which of the following is not a valid way to access the elements of an object in JavaScript?

object.property
object['property']
object[property]
object.getProperty()

What is the purpose of the Array.prototype.reduce() method in JavaScript?

To reduce an array to a single value
To reduce an array to a new array
To reduce an array to an object
To reduce an array to a string

Which of the following is not a valid way to create a new JavaScript object?

const object = {};
const object = new Object();
const object = { property: value };
const object = [];

What is the purpose of the Object.freeze() method in JavaScript?

To prevent an object from being modified
To prevent an object from being deleted
To prevent an object from being accessed
To prevent an object from being serialized

Which of the following is not a valid way to iterate over the properties of an object in JavaScript?

for (const property in object) { ... }
for (const [property, value] of Object.entries(object)) { ... }
object.forEach((property, value) => { ... })
object.map((property, value) => { ... })

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