testcases = 100000;
x = [];
for(let i = 0; i < testcases; i++) {
if(i % 2 == 0) {
x[i] = i;
} else {
x[i] = "somestring";
}
}
x.filter(y => {
if (typeof y == typeof 2) {
return y % 2 == 0;
}
return false;
});
x.filter(y => y % 2 === 0)