how to return value in array some in javascript code example

Example 1: javascript some

const age= [2,7,12,17,21];

age.some(function(person){
return person > 18;}); //true

//es6
const age= [2,7,12,17,21];
age.some((person)=> person>18); //true

Example 2: javascript some

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

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

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