const sumAll = function(minimum, maximum) { let sum=0; let min = minimum let max = maximum if (typeof(min) !== 'number' || typeof(max) !== 'number' || min < 0 || max < 0){ return 'ERROR' } else if(min > max){ min = maximum max = minimum } for (let i = min;i <= max; i++){ sum += i } return sum }; console.log(sumAll(1,5) === 15?true:false) // Do not edit below this line module.exports = sumAll;