Just curious Why then
is-hidden != null instead of is-hidden !== null Angel "Java" Lopez @ajlopez On Sun, Aug 17, 2014 at 9:45 AM, stephanos <[email protected]> wrote: > Thank you! It make sense now :) > > > On Sunday, August 17, 2014 2:44:23 PM UTC+2, [email protected] wrote: > > The boolean metadata is a type hint telling the ClojureScript compiler > that is-hidden is boolean. Knowing is-hidden is a boolean allows > ClojureScript to compile to > > > > if (is-hidden){ > > } > > else { > > } > > > > instead of > > > > if (is-hidden != null && is-hidden !== false){ > > } > > else { > > } > > > > if the type isn't known to be a boolean. The extra checks are needed > because ClojureScript has only two values that evaluate to false: false and > nil. JavaScript evaluates false, null undefined, "", 0, and NaN to be false. > > > > About the only time you need to use the boolean type hint is in > performance sensitive code where the compiler can't infer the type of a var > (like a parameter passed into a function). > > > > I hope this answers your question > > > > Peter Schuck > > -- > Note that posts from new members are moderated - please be patient with > your first post. > --- > You received this message because you are subscribed to the Google Groups > "ClojureScript" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/clojurescript. > -- Note that posts from new members are moderated - please be patient with your first post. --- You received this message because you are subscribed to the Google Groups "ClojureScript" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/clojurescript.
