Test if All Array Elements Are Truthy

Introduction

In this lab, we will explore a useful JavaScript function called all. This function tests whether all elements in an array pass a given condition and returns a Boolean value. We will learn how to use this function with different types of arrays and conditions to make our code more efficient and concise.

Skills Graph

Checking if All Array Elements Are True

To check if all elements in a collection are true, you can use the Array.prototype.every() method. This method takes a predicate function as an argument and returns true if the function evaluates to true for all elements in the array.

To simplify the code, you can use a function called all which takes an array and an optional predicate function as arguments. The function uses Array.prototype.every() to check if all elements in the array return true based on the provided function. If no function is provided, Boolean is used as a default.

Here's an example of how to use the all function:

const all = (arr, fn = Boolean) => arr.every(fn);

all([4, 2, 3], (x) => x > 1); // true
all([1, 2, 3]); // true

Summary

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