How to Check If a Value Exists in an Array in JavaScript
Topic: JavaScript / jQueryPrev|Next
Answer: Use the indexOf() Method
You can use the indexOf() method to check whether a given value or element exists in an array or not. The indexOf() method returns the index of the element inside the array if it is found, and returns -1 if it not found. Let's take a look at the following example:
Example
Try this code »<script>
var fruits = ["Apple", "Banana", "Mango", "Orange", "Papaya"];
// Check if a value exists in the fruits array
if(fruits.indexOf("Mango") !== -1){
alert("Value exists!")
} else{
alert("Value does not exists!")
}
</script>ES6 has introduced the includes() method to perform this task very easily. But, this method returns only true or false instead of index number, as you can see here:
Example
Try this code »<script>
var fruits = ["Apple", "Banana", "Mango", "Orange", "Papaya"];
alert(fruits.includes("Banana")); // Outputs: true
alert(fruits.includes("Coconut")); // Outputs: false
alert(fruits.includes("Orange")); // Outputs: true
alert(fruits.includes("Cherry")); // Outputs: false
</script>All modern browsers supports the includes() method and it is preferred for modern applications.
Please check out the tutorial on JavaScript Arrays to learn more about the arrays.
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