If you want to check if one array is a subset of another array then you could try something like this:

let array1 = [3, 1, 2, 5];
let array2 = [1, 2, 3];

let isSubset = (arr1,arr2) => arr1.every(x=> arr2.includes(x));

console.log('Is array1 a subset of array2?',isSubset(array1,array2));
console.log('Is array2 a subset of array1?',isSubset(array2,array1));

Here first console.log returns false because not all elements of array1 are present in array2.
But when we swap params inside isSubset function we now check if all of the elements of array2 are present in array1. In this case we're getting true state.