Correctly encode twitter sharing url (#935)

Author: cderv

NEWS.md

@@ -2,6 +2,8 @@
 
 ## BUG FIXES
 
+- Correctly encode the document title when creating the twitter sharing link from a bookdown chapter (thanks, @maelle, #934).
+
 - Make sure `search_index.json` contains valid characters for the JSON format (thanks, @wlandau, #913).
 
 ## MINOR CHANGES

inst/resources/gitbook/js/plugin-sharing.js

@@ -23,7 +23,7 @@ gitbook.require(["gitbook", "lodash", "jQuery"], function(gitbook, _, $) {
             'icon': 'fa fa-twitter',
             'onClick': function(e) {
                 e.preventDefault();
-                window.open("http://twitter.com/intent/tweet?text="+document.title+"&url="+encodeURIComponent(location.href)+"&hashtags=rmarkdown,bookdown");
+                window.open("http://twitter.com/intent/tweet?text="+encodeURIComponent(document.title)+"&url="+encodeURIComponent(location.href)+"&hashtags=rmarkdown,bookdown");
             }
         },
         'linkedin': {