It's quick and straightforward and has no weird overhead. This might be my personal most used option. There are a couple of options for us here. How can we check whether a user's role is part of this list?įor the sake of this article, we'll assume the user's role is a simple string like so: const role = 'user'

These valid roles are defined in an array. So only people with that specific role should be able to continue. We have some roles that can access a particular page.

The some() method: the some() method returns a boolean indicating whether at least one element in the array passed the test implemented by the provided function.Different ways to check if an array includes a value in Vanilla JavaScript 27 Jan, 2022.

The filter() method: the filter() method creates a new array with all elements that pass the test implemented by the provided function.The find() method: the find() method returns the value of the first array element that satisfies the given function.The indexOf() method: the indexOf() method returns the first index by which the given element can be found in the array, or -1 if it is not present.The includes() method: the includes() method returns a boolean indicating whether the element is present in the array.There are several ways in JavaScript to check if an element exists in an array: How to check if an element exists in a JavaScript array? You can also convert an array to JSON, get a sum of array elements, convert a string to an array, or convert an array to a string. JavaScript provides built-in methods for merging, joining, slicing, reversing, copying, reducing, inserting, clearing, and cloning arrays. Each element in an array has its own index, allowing you to access an element directly by index or iterate through the array with a 'for loop'. A JavaScript array is created using square brackets '' or using the 'new Array()' constructor. What is an array in JavaScript?Īn array is a special built-in object in JavaScript that allows storing multiple elements of different types in a single variable. JavaScript can also be used on the server side ( Node.js), making it a universal language for all devices and platforms. JavaScript is a client-side programming language that runs in the web browser, allowing for real-time manipulation and updates of content on a web page.

Javascript check if array