Test if All Array Elements Are Falsy

Introduction

In this lab, we will explore the concept of testing whether all elements in an array are falsy using JavaScript. We will use the none() function which checks if the provided predicate function returns false for all elements in a collection. Through practical examples, we will see how this function can be used to efficiently manipulate arrays in JavaScript.

Skills Graph

Function to Test if All Array Elements Are Falsy

To test if all elements in an array are falsy, follow these steps:

1. Open the Terminal/SSH and type node to start practicing coding.
2. Use Array.prototype.some() to test if any elements in the collection return true based on the provided predicate function.
3. If you omit the second argument, fn, the function will use Boolean as a default.
4. The function returns true if all elements in the array are falsy, and false otherwise.

Here is an example implementation of the function:

const none = (arr, fn = Boolean) => !arr.some(fn);

You can use the function as follows:

none([0, 1, 3, 0], (x) => x == 2); // true
none([0, 0, 0]); // true

Summary

Congratulations! You have completed the Test if All Array Elements Are Falsy lab. You can practice more labs in LabEx to improve your skills.