1var fruits = ["Banana", "Orange", "Apple", "Mango"];
2
3var n = fruits.includes("Mango"); // true
4
5var n = fruits.includes("Django"); // false

1function checkInput(input, words) {
2 return words.some(word => new RegExp(word, "i").test(input));
3}
4
5console.log(checkInput('"Definitely," he said in a matter-of-fact tone.', 
6["matter", "definitely"]));

1const fruits = ['apple', 'banana', 'mango', 'guava'];
2
3function checkAvailability(arr, val) {
4  return arr.some(arrVal => val === arrVal);
5}
6
7checkAvailability(fruits, 'kela');   // false
8checkAvailability(fruits, 'banana'); // true

1private boolean ZitAlInArray(int value, List<Integer> list) {
2  return array.indexOf(value) > -1;
3}
4
5private boolean zitAlInArray(int[] array, int index) {
6		for (int i = 0; i < index; i++) {
7			if (array[i] == array[index]) {
8				return true;
9			}
10		} 
11		return false;
12	}
13

1// To check if an array contains a string 
2
3const colors = ['red', 'green', 'blue'];
4const result = colors.includes('red');
5
6console.log(result); // true
7
8// Or 
9
10const colors = ['Red', 'GREEN', 'Blue'];
11const result = colors.map(e => e.toLocaleLowerCase())
12                     .includes('green');                          
13
14console.log(result); // true