If you want to check if a string is contained in an array in JavaScript, you can use some built-in methods in JavaScript include indexOf()
includes()
join()
and search()
methods. Let’s find out what those methods are through some examples below.
How to check if a string is contained in an array in JavaScript?
I would follow two directions as follows:
- Check directly.
- Bring the array to the handle and then search.
Check directly
Syntax:
array.indexOf(element, start)
Parameters:
- element: This is any string.
- start: This is where the function starts looking.
Example:
var fruits = ["Lemon", "Orange", "Apple", "Cherry"]; // Check directly if (fruits.indexOf("Apple") !== -1) { console.log("fruits have Apple"); } else { console.log("fruits have not Apple"); }
Output:
fruits have Apple
In the above example, we can see that I compared the return result of the indexOf() method with -1 because after using the indexOf() method, it will return the address of the string. The return value will be -1, so I compare the result of the method with -1.
includes() method
Syntax:
array.includes(element, start)
Parameters:
- element: This is any string.
- start: This is where the function starts looking.
Example:
var fruits = ["Lemon", "Orange", "Apple", "Cherry"]; // Check directly if (fruits.includes("Apple")) { console.log("fruits have Apple"); } else { console.log("fruits have not Apple"); }
Output:
fruits have Apple
Unlike the indexOf() method, it will return a boolean value, so we use it as a condition for the if statement.
Return the array to the string and then search
In this method, we need to return the array to a string. I will use two methods, join() and toString().
join() method
Syntax:
array.join(separator)
Parameter:
- separator: A substring used to concatenate array elements.
Example:
var fruits = ["Lemon", "Orange", "Apple", "Cherry"]; // Convert array to string var fruitsStr = fruits.join(", "); console.log(fruitsStr);
Output:
Lemon, Orange, Apple, Cherry
toString() method
Syntax:
array.toString()
Example:
var fruits = ["Lemon", "Orange", "Apple", "Cherry"]; // Convert array to string var fruitsStr = fruits.toString(); console.log(fruitsStr);
Output:
Lemon, Orange, Apple, Cherry
After returning the array to the string, I will search the string with the search() method or any string search method.
search() method
Syntax:
string.search(searchValue)
Parameter:
- searchValue: is the string the value you want to search.
Example:
var fruits = ["Lemon", "Orange", "Apple", "Cherry"]; // Convert array to string var fruitsStr = fruits.toString(); // Check-in array if (fruitsStr.search("Apple") !== -1) { console.log("fruits have Apple"); } else { console.log("fruits have not Apple"); }
Output:
fruits have Apple
search() method returns the position of the passed parameter value and will return -1 when the passed parameter is not found. So, in the above example, I compared the return value of the search() method with -1 to see if the string to check is present.
Summary
I have shown you some methods to check if a string is contained in an array in JavaScript. Try them out. I think they will help you and your program. Good luck!
Maybe you are interested:
- Check if Array contains Empty Elements in JavaScript
- Check if String contains Substring from Array in JS
- Check if an Array contains Duplicates in JavaScript

My name is Tom Joseph, and I work as a software engineer. I enjoy programming and passing on my experience. C, C++, JAVA, and Python are my strong programming languages that I can share with everyone. In addition, I have also developed projects using Javascript, html, css.
Job: Developer
Name of the university: UTC
Programming Languages: C, C++, Javascript, JAVA, python, html, css