Cljs: How to convert a time property from string to time for arithmetic?

Questions & Help Queries
1

So I have a bunch of blocks with from:: and to:: properties, formatted as hh:mm. I’m trying to figure out how to do some arithmetic with those, specifically, calculate duration. I tried

(- (:to properties) (:from properties))

in the view, which results in NaN. The same with “+” results in the times being concatenated, so obviously, they are strings. I have never touched cljs before. I just seem to get the basic idea because I learned Lisp in school as a teenager.
How would I go about getting the properties converted into times that I can use for calculations?

2

Got something but it doesn’t look pretty, especially the output…

              (int (/
              (- 
                (+ (* (int (subs (:to properties) 0 2)) 60) (int (subs (:to properties) 3 5)) )
                (+ (* (int (subs (:from properties) 0 2)) 60) (int (subs (:from properties) 3 5)) )
              )
              60))
              ":"
              (mod
              (- 
                (+ (* (int (subs (:to properties) 0 2)) 60) (int (subs (:to properties) 3 5)) )
                (+ (* (int (subs (:from properties) 0 2)) 60) (int (subs (:from properties) 3 5)) )
              )
              60)

Is there a way to format number output, like limit decimals or force leading zeros?

3

When parsing strings, consider using clojure.string/split

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