Algorithm design for a js loop structure

Question

I got an array [1,2,3,4]

I need first to run over [2] that was chosen, set his styles, and than after run over the other children and reset their styles.

At the moment, my algorithm is as following:

for item in array
    if item == chosenEl
        set chosen classes
for item in array
    if item != chosenEl
        reset chosen classes for the rest of the children

Or coffe:

for item in @array
    if item.element is element
        item.selected = true
        item.element.classList.add @selectedClass
        item.element.focus()
for item in @array
    if item.element isnt element
        item.selected = false
        item.element.classList.remove @selectedClass

I need to design the function like that, and not as a simple forElse loop, due to some restrictions in me framework.

How can I improve this code?

Thank you.

Explanation- The reason I need this design, is due to duplicated calls for 2 different functions, that conflict one the other.

I'm developing an app for LG TV. The LG TV has its own libraries. Now in my function I set the styles of chosen elements. Byt when I focus to the chosen element, I activate the LG TV onFocus listener, which in his turn control the selected styles.

So when I loop the second or third child, I set again the selected styles, of cleared elements. TLDR but thats how the loops conflicting each other. One interrupting the work of other.

The code was not written by me. I entered an existing project, and I havent written this function, so i cannot just remove the Focus() function.

Sunny · Accepted Answer · 2013-03-01 02:19:36Z

2

Instead of looping twice, consider below code

for item in array
{
    if item == chosenEl
    {
        set chosen classes
        continue; <--use this to return to next iteration without executing next statements
    } 
   reset chosen classes for the rest of the children
}

It will be O(n) instead of O(n) + O(n)

Edit:

I am sorry, I didn't understand your explanation. If all you need is a function which you can repeatedly call then here it is, call resetStyles multiple times by passing selected value. Please note since you haven't provided exact data types, I assumed them as integers.

<script>
var resetStyles = function(selecteditem)
{
   var arr = [1,2,3,4];
   for(var i=0; i < arr.length; i++)
   {
      if(arr[i] == selecteditem)
      {
        //set class here

        continue;
      }
      //remove class here
   }
};
resetStyles(2);//call this by changing the values
</script>

edited Mar 1, 2013 at 2:19

answered Feb 28, 2013 at 18:52

Sunny

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1 Comment

neoswf Over a year ago

Hi @Sundeep. Thank you for your comment, but as I explained in the OP, I cannot run a simple ForElse due to restrictions of my FW. I will explain upstairs what is my restriction, that demanded me to think about this design.

Niet the Dark Absol · Accepted Answer · 2013-02-28 18:51:30Z

1

Why are you looping twice? Far easier to just do:

for( var i=0, l=array.length; i<l; i++) {
    if( item == chosenEl) {
        // set styles
    }
    else {
        // clear styles
    }
}

answered Feb 28, 2013 at 18:51

Niet the Dark Absol

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1 Comment

neoswf Over a year ago

Hi @Kolink. Thank you for your comment, but as I explained in the OP, I cannot run a simple ForElse due to restrictions of my FW. I will explain upstairs what is my restriction, that demanded me to think about this design.

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