switch line class in clojurescript with if boolean variable

Question

how can I switch the li class in a list with clojurescript, when the @switchvar is true all odd lines should be active, in the other case the even lines should be active

I tried an if statement, nothing happens.

(defn listitems [items]
  [:ul
   (for [item items]
     ^{:key item} [:li {:class 
        (if (@switchvar true) 
            ((odd? item) "active") 
            ((even? item) "active") ) 
      } "Item " item ])])

Chris Murphy · Accepted Answer · 2017-03-30 12:05:41Z

0

You are calling the function that is within the switchvar atom, and giving it true as a parameter. Better to just deref (@) it:

(defn listitems [items]
  [:ul
   (for [item items
         idx (range (count items))]
     ^{:key item} [:li {:class
                        (if (and (odd? idx) (odd? @switchvar))
                          "active"
                          "inactive")
                        } "Item " item])])

I made a change so that there's an idx that will vary with each list item. So both @switchvar and idx can change. I hope you can alter this code to suit your exact needs.

edited Mar 30, 2017 at 12:05

answered Mar 29, 2017 at 23:08

Chris Murphy

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2 Comments

bluelemonade Over a year ago

ok, I understand a little bit more. but, I want to switch the even odd active thing when switchvar changes. In the line with "active" I will do something like ((odd? item) "active") and in inactive ((even? item) "active")

Chris Murphy Over a year ago

I made a change to introduce idx. You should note that code like ((odd? item) "active") does not make sense because odd? is a function that returns a boolean - and then your code invokes that boolean. And you can't invoke a boolean. You can invoke strange things like maps and keywords (where they act as functions), but you can't invoke a boolean.

akond · Accepted Answer · 2017-03-29 16:54:28Z

0

Your if statement does not seem right. You could do something like that:

[:ul (map #(-> [:li {:class %2} "item" %1]) 
          items 
          (cycle ["active" "non-active"]))]

edited Mar 29, 2017 at 16:54

answered Mar 29, 2017 at 15:53

akond

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3 Comments

bluelemonade Over a year ago

this switch the odd and even li elements, I want to change the active and not active class

bluelemonade Over a year ago

ok, I try to understand. where is the problem with my for loop an the if statement?

bluelemonade Over a year ago

just missing the @switchvar, I want to change the order or the active non-active class

bluelemonade · Accepted Answer · 2017-03-30 15:52:27Z

0

thanks@all, I got a good start into clojure with your hints. switchvar is actually boolean. I changed the first "inactive" to another if clause.

(defn lister-items2 [items]
  [:ul
   (for [item items ]
     ^{:key item} [:li {:class
                    (if (and (odd? item) (true? @switchvar))
                      "active"
                      (if (and (even? item) (false? @switchvar))
                        "active"
                        "inactive"))
                    } "Item " item])])

answered Mar 30, 2017 at 15:52

bluelemonade

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