function removeFalsy(arr) {
   var indexNum;
   for (item of arr) {
        if (item === null || item === 0 || item === "" || item === false || item === undefined || item === NaN) {
            indexNum = arr.indexOf(item);
            arr.splice(indexNum,1)
        }         
    }
    return arr;
}

console.log(removeFalsy([NaN, 0, 15, false, -22, "", undefined, 47, null]));