why use (array || []).some 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: some js es6

const array = [1, 2, 3, 4, 5];

// checks whether an element is even
const even = (element) => element % 2 === 0;

console.log(array.some(even));
// expected output: true