How to Check If a Value Exists in an Array in JavaScript

  1117 views   2 years ago Javascript

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:

    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!")

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:

    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


Author : Harsukh Makwana
Harsukh Makwana

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