There are different methods in JavaScript that you can use to search for an item in an array. Which method you choose depends on your specific use case.

For instance, do you want to get all items in an array that meet a specific condition? Do you want to check if any item meets the condition? Do you want to check if a specific value is in the array? Or do you want to find the index of the value in the array?

For all these use cases, JavaScript’s Array.prototype methods have you covered. In this article, we will discuss four methods we can use to search for an item in an array. These methods are:

Filter
Find
Includes
IndexOf

Let’s discuss each of them.

Array.filter()

We can use the Array.filter() method to find elements in an array that meet a certain condition. For instance, if we want to get all items in an array of numbers that are greater than 10, we can do this:

const array = [10, 11, 3, 20, 5];

const greaterThanTen = array.filter(element => element > 10);

console.log(greaterThanTen) //[11, 20]

The syntax for using the array.filter() method is the following:

let newArray = array.filter(callback);

where

newArray is the new array that is returned
array is the array on which the filter method is called
callback is the callback function that is applied to each element of the array

If no item in the array meets the condition, an empty array is returned. You can read more about this method here.

There are times when we don’t need all the elements that meet a certain condition. We just need one element that matches the condition. In that case, you need the find() method.

Array.find()

We use the Array.find() method to find the first element that meets a certain condition. Just like the filter method, it takes a callback as an argument and returns the first element that meets the callback condition.

Let’s use the find method on the array in our example above.

const array = [10, 11, 3, 20, 5];

const greaterThanTen = array.find(element => element > 10);

console.log(greaterThanTen)//11

The syntax for the array.find() is

let element = array.find(callback);

The callback is the function that is executed on each value in the array and takes three arguments:

element - the element being iterated on (required)
index - the index/position of the current element (optional)
array - the array that find was called on (optional)

Note, though, that if no item in the array meets the condition, it returns undefined.

What if, though, you want to check if a certain element is in an array? How do you do this?

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