check if value exists in array js code example

Example 1: check if array does not contain value javascript

var fruits = ["Banana", "Orange", "Apple", "Mango"];

var n = fruits.includes("Mango"); // true

var n = fruits.includes("Django"); // false

Example 2: how to check if item is in list js

var myList=["a", "b", "c"];
mylist.includes("d")//returns true or false

Example 3: check value exist in array javascript

[1, 2, 3].includes(2);     // true
[1, 2, 3].includes(4);     // false
[1, 2, 3].includes(1, 2);  // false (second parameter is the index position in this array at which to begin searching)

Example 4: javascript check if in array

var extensions = ["image/jpeg","image/png","image/gif"];          
if(extensions.indexOf("myfiletype") === -1){
	alert("Image must be .png, .jpg or .gif");
}

Example 5: Checking whether a value exists in an array javascript

const fruits = ['apple', 'banana', 'mango', 'guava'];

function checkAvailability(arr, val) {
  return arr.some(arrVal => val === arrVal);
}

checkAvailability(fruits, 'kela');   // false
checkAvailability(fruits, 'banana'); // true