Javascript 'switch' problem

JavaScript
#1

I’m trying out some new found coding skills and still have a lot of room to go so I know this function maybe a tad crude, but I’m having trouble with getting a correct ‘total’. The function takes any of four inputs values and multiplies them according to different values of ‘select/options’ and calculates a ‘total’. No matter the input value or the value of the ‘select’ option, my total comes up to ‘0’. Anyone tell me what I did wrong?

function submitAll() {

            switch (fOne) {

                case 'weekly':

                    cOne *= 4;

                    break;

                case 'biweekly':

                    cOne *= 2;

            }

            switch (fTwo) {

                case 'weekly':

                    cTwo *= 4;

                    break;

                case 'biweekly':

                    cTwo *= 2;

            }

            switch (fThree) {

                case 'weekly':

                    cThree *= 4;

                    break;

                case 'biweekly':

                    cThree *= 2;

            }

            switch (fFour) {

                case 'weekly':

                    cFour *= 4;

                    break;

                case 'biweekly':

                    cFour *= 2;

            }

            total = cOne + cTwo + cThree + cFour;

            document.getElementById("display").innerHTML = 'Your total income is; ' + total;

        }
#2

I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

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See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).

#3

It seems to work for me:

const fOne = 'weekly'
let cOne = 1

const fTwo = 'monthly'
let cTwo = 2

const fThree = 'biweekly'
let cThree = 3

const fFour = 'weekly'
let cFour = 4

function submitAll() {
  switch (fOne) {
    case "weekly":
      cOne *= 4;
      break;
    case "biweekly":
      cOne *= 2;
  }

  switch (fTwo) {
    case "weekly":
      cTwo *= 4;
      break;
    case "biweekly":
      cTwo *= 2;
  }

  switch (fThree) {
    case "weekly":
      cThree *= 4;
      break;
    case "biweekly":
      cThree *= 2;
  }

  switch (fFour) {
    case "weekly":
      cFour *= 4;
      break;
    case "biweekly":
      cFour *= 2;
  }

  total = cOne + cTwo + cThree + cFour;
  console.log('total', total)
}

submitAll()
// total 28

It seems to work for me. Again, I think this isn’t the best approach - you shouldn’t depend on all those out of scope variables in the function and really that function has too much repetition. I think you’re making this too difficult, as we discussed before.

#4

What about something like this:

const getSubTotal = (flag, value) => {
  switch (flag) {
    case 'weekly':
      return value * 4;
    case 'biweekly':
      return value * 2;
    default:
      return value
  }
}

function submitAll() {
  const total = getSubTotal(fOne, cOne) + getSubTotal(fTwo, cTwo) + getSubTotal(fThree, cThree) + getSubTotal(fFour, cFour);
  // ...

I still have some objects, but at least that repetition is gone.

#5

Ok, now I think I’m beginning to understand what your getting at, I think. What I believe your doing is calling the subTotal function inside the total function. I know its hard to teach an old dog new tricks so please bare with me.

#6

Right, there is a principle in coding - DRY - Don’t Repeat Yourself. You are basically doing the same things 4 times in a row. You can get away with doing the same things twice maybe, but not 4 times. It’s easier to read and you are only doing it in one place so there it is easier to debug.

1 Like
#7

the reason why you get 0 is probably due to the first assignment of cOne, cTwo..., if you initialize them with 0, then you will get 0, because cOne *= 4; is like cOne = cOne*4 and if cOne === 0 then it will become like cOne = 0.
I just assumed, i don’t know, can you put the whole code?

#8

I used html input values to try different values. There was something wrong in my getElementById().value. I misspelled document then copied and pasted the same mistake four times. Put S*&% in, get S*&^ out right?