gistfile1.txt

function multiplyByThree(array) {
  var multiplier = 3;
  
  // Handle undefined or null inputs
  if (!array) {
    throw new Error("Argument is undefined or null");
  }
  
  // Handle non-array inputs
  if (!Array.isArray(array)) {
    throw new Error("Argument is not an array");
  }
  
  var result = [];
  for (var i = 0; i < array.length; i++) {
    if (typeof array[i] !== "number") {
      throw new Error("Array must contain valid integers only");
    } else {
      result[i] = array[i] * multiplier;
    }
  }
  
  return result;
}