React will escape HTML entities (like
×) in the text elements.
You could just use literal character:
× or unicode code, which is converted to the character by Cljs compiler:
HTML entities work in React JSX because JSX will unescape the entity code to literal character.
You can do the same in ClojureScript by using
(:require [goog.string :as gstr]))
(defn comp 
[:h1 "Foo" (gstr/unescapeEntities "×")])
Note: Yes, this can be inconvenient, but Reagent can't do this automatically as finding and replacing entities during runtime would be slow.