const intArr = [3,10,25,2,7]

function customForEach(arr,fn){

    for(let i=0; i<arr.length; i++){

        fn(arr[i] % 2 == 0, () => {

            console.log(arr[i], "is even");

        });

    }

}

function unless(test, then) {

  if (test) then();

}

customForEach(intArr,unless);