Array map() Function in JavaScript

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What does the map() function do?

Filters the array based on a condition

Reduces an array into a single value

Sorts the array in ascending order

Creates a new array of the same size with transformed values (correct)

How is the reduce() function different from other array functions?

It reduces an array into a single value (correct)

It duplicates the original array

It creates a new array based on a condition

It transforms each element of the array

In the reduce() function, what are the two required parameters for the callback function?

Current value and next element

Previous value and current element (correct)

Current value and previous element

Previous value and next element

What does the total variable represent in the reduce() example provided?

Sum of all values in the array Signup and view all the answers

If you wanted to create a new array by filtering based on a specific condition, which function would be more appropriate than map()?

filter() Signup and view all the answers

What is the purpose of using the map() function with DOM nodes as shown in Listing 10.2?

To create a new list of DOM elements with transformed values Signup and view all the answers

What does the 'sort()' function do in JavaScript?

Sorts an array in ascending order Signup and view all the answers

When sorting an array of objects based on a property, what does the compare function return if two values are equal?

0 Signup and view all the answers

Which method is used to create multiple instances of objects with the same properties efficiently in JavaScript?

Prototypes Signup and view all the answers

In JavaScript, what does the 'prototype' property of a function object initially contain?

An empty object Signup and view all the answers

Why is using prototypes considered superior when creating objects with methods in JavaScript?

It defines the method only once for all instances Signup and view all the answers

Which syntax can be used for a concise comparison function when sorting an array based on object properties?

(a,b) => a.property < b.property ? -1 : 1 Signup and view all the answers

Array map() Function in JavaScript

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Questions and Answers

What does the map() function do?

How is the reduce() function different from other array functions?

In the reduce() function, what are the two required parameters for the callback function?

What does the total variable represent in the reduce() example provided?

If you wanted to create a new array by filtering based on a specific condition, which function would be more appropriate than map()?

What is the purpose of using the map() function with DOM nodes as shown in Listing 10.2?

What does the 'sort()' function do in JavaScript?

When sorting an array of objects based on a property, what does the compare function return if two values are equal?

Which method is used to create multiple instances of objects with the same properties efficiently in JavaScript?

In JavaScript, what does the 'prototype' property of a function object initially contain?

Why is using prototypes considered superior when creating objects with methods in JavaScript?

Which syntax can be used for a concise comparison function when sorting an array based on object properties?

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