javascript build multidimensional arrays and objects

Question

I'm trying to build an array/object based on user-input to a form that has radios, checkboxs with radios, textfields with radios, and selects. I want the final array/object to be consolidated such that activated form-elements with repeated names are collapsed into a single object:

~~data = { name0 = (value0,value4), // checkbox name1 = (value2), // radio name2 = (value5), // select>option name4 = (''), // non-response name5 = (NULL) // form element was disabled/hidden }~~

Javascript seems to be rather picky, so I'm having some trouble. I've broken it up into 3 pieces (Arr1,Arr2,Arr3), but it seems like the first bit only retains the last form element and the second bit stops for each name after it's been encountered.

Code in JSfiddle: http://jsfiddle.net/jshado1/5Y7sn/12/

EDIT: What I want the final array to look like for the example in the fiddle is:
(with all alphas unchecked, beta=1 checked, beta=2 checked, and delta=3 selected)

data : {
    { 'alpha'    : '' },
    { 'beta'     : '1','2' },
    { 'delta'    : '3' },
    { 'continue' : 'continue' }
}

(eventually I'll filter out [continue] using a more precise jQuery selector and put the button outside of a div)

It's really hard to understand what exactly you wont to archive with your fiddle but I'm still trying... — Matteo B.
– Matteo B., Commented Dec 28, 2011 at 0:15

nnnnnn · Accepted Answer · 2011-12-28 00:35:11Z

4

I'm not quite sure about your goal here, but I can see some problems with your code:

You have a global variable I, which is initialised to 0 but never changed so when you use it as an index to Arr1[I] inside your .each() loop you will continuously overwrite array element 0.
You have Arr2[n] = +1; when you probably meant Arr2[n] += 1; or Arr2[n]++;
Your for loop uses an undeclared i index, though that should work (it's just that i is implicitly global, and it's always better to declare all your variables).
In the middle of the switch you have Arr3[nom] += val; but Arr3[nom] is never initialised to 0 so effectively you are saying undefined += val which would give NaN.
In your switch statement you have case ("checkbox" || "radio"):, which is equivalent to case "checkbox" so you never match on "radio". You want a fall-through to cover both values.

Update your switch:

switch(type) {
    case "checkbox":
        // fall-through
    case "radio":
        if (state) {
           if (Arr2[nom] > 1) {
               Arr3[nom] += val;
           } else {
               Arr3[nom] = val;
           }
        }
        break;
    case "text":
        Arr3[nom] = val;
        break;
    default:
        break;
}

It is at this point that I agree with @Matmarbon and give up. I'd suggest you fix all of the above and get back to us.

edited Dec 28, 2011 at 0:35

answered Dec 28, 2011 at 0:22

nnnnnn

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6 Comments

Jakob Jingleheimer Over a year ago

Whoops, I++; must have got deleted at some point (it was at the end of the .each()). #3: I thought the for loop declares i and when it does that, i only exists inside the loop? (I'm pretty sure that's how it works in php, shell, and C) #4: I think I need to initialise Arr3[nom] as an array and use push(val). #5: Doesn't the () create a subroutine?

Jakob Jingleheimer Over a year ago

#2, Arr2[n] holds a count of the number of instances of n. ex Arr2["cups"] = 2.

Jakob Jingleheimer Over a year ago

I've fixed those issues, but now I think I have different ones: jsfiddle.net/jshado1/5Y7sn/23

nnnnnn Over a year ago

Regarding your comments about the different points I made: #2 yes, I assumed that but you weren't adding 1 to count, you were setting to 1 each time. #3 any variable used without a var declaration has global scope, and JavaScript doesn't have block scope like Java or C#, it only has function and global scope. #4 Your code looked like you were trying to keep a sum of the values, but yes if you want to remember individual values then an array and .push() would work. #5 No, and even if it did it wouldn't make sense for a case.

nnnnnn Over a year ago

Regarding your new fiddle, here's an updated one that runs: jsfiddle.net/5Y7sn/27 I fixed a few problems. Lines 22 & 28 - don't use var to create array elements: Arr2 is already declared so you create a new element with Arr2[someindex]=somevalue. Line 38 needed a semicolon rather than a comma (otherwise it tried to treat the if statement that followed as a variable declaration). I think lines 40-44 should be saying if (Arr3[nom] === undefined) Arr3[nom] = []; and then just Arr3[nom].push(val); otherwise you were never actually initialising that array element to be an array.

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Matteo B. · Accepted Answer · 2011-12-28 00:51:38Z

3

Okay.. don't know where to start.. first you should use :s instead of =s to define the objects properties. Then secondly it's really no problem to nest objects. An attribute of an object can ever by another object. So var x = { 'a' : { { 1 : {} } : 'the value' } } is a valid definition.

Further infos when I understood your JSFiddle ^^

EDIT: Here is a possible solution if I understood your question right: http://jsfiddle.net/5Y7sn/8/

edited Dec 28, 2011 at 0:51

answered Dec 28, 2011 at 0:18

Matteo B.

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2 Comments

Jakob Jingleheimer Over a year ago

oow, that's almost it, but I want names with unchecked elements to be '' instead of 0 (see the new example I added to my question). Thanks!!

Jakob Jingleheimer Over a year ago

I think in both of yours, the values of alpha and beta are being stored as strings instead of arrays/objects: I would expect there to be a comma between beta:"12" (where beta=1 and beta=2 are both checked). Besides that, it looks right.

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