有人可以解释为什么我得到 9 和 5 而不是 36880 和 375

Question

For my return, I'm getting 9 and 5 instead of 362880 and 375. Can someone explain what I missed?

 function multiplyAll(num){ // declare a function name multyplyAll with a num parameter for (let i = 0; i < num.length; i++){ // for loop to iterate base on the length of the parameter. num *= num[i] // multiplies them all together. } return num // function outpout } console.log(multiplyAll(9, 4, 5, 6, 7, 2, 1, 8, 3)) // should log: 362880 console.log(multiplyAll(5, 5, 5, 3)) // should log: 375

Answer 1

When you are using num without rest parameters then only the first value will get assign to num . You are treating like num is an array but num is just of type number

There is no length property on num , Because num is of type number. It won't run the for loop and return the first element ie 9 and 5

You should use collect then in to an array using rest parameters

 function multiplyAll(...num) { // declare a function name multyplyAll with a num parameter let res = 1; for (let i = 0; i < num.length; i++) { // for loop to iterate base on the length of the parameter. res *= num[i]; // multiplies them all together. } return res; // function outpout } console.log(multiplyAll(9, 4, 5, 6, 7, 2, 1, 8, 3)); // should log: 362880 console.log(multiplyAll(5, 5, 5, 3)); // should log: 375

You can also use reduce here as:

 function multiplyAll(...num) { return num.reduce((acc, curr) => acc * curr, 1); } console.log(multiplyAll(9, 4, 5, 6, 7, 2, 1, 8, 3)); // should log: 362880 console.log(multiplyAll(5, 5, 5, 3)); // should log: 375