Array some() and every()

.some() it's incredibly helpful, especially when paired with claims systems:
const isNeg = x => x < 0;

[1, 3, 7, -4, 8].some(isNeg);
// => true

[1, 3, 7, 72, 0, 21].some(isNeg);
// => false
.every() will check for all items in array and expects all to be evaluated as truthy:
[4, 3, 2, 1].every(x => x >= 1);
//=> true

[4, 3, 2, 1].every(x => x < 1);
// => false
Sometimes we may need the index and/or the initial array for complex validations and this is accessible as usual by accepting beyond the element, also the index and intital array as parameters.
const array = [4, 3, 2, 1];
array.some((element, index, array) => {
  // advanced checks here
});