Sample code demonstrating https://github.com/jlr/rainbow-delimiters/issues/4

wikipedia.js

//////////////////////////////////////////////////////////////////////
// Wikipedia
//////////////////////////////////////////////////////////////////////

(function(w) {
  var call_wikipedia_api = function(data, callback) {
    $.ajax({
      url: "http://en.wikipedia.org/w/api.php",
      data: $.extend({ format: "json" }, data),
      dataType: "jsonp",
      success: callback
    });
  };

  w.wikipedia = {
    full_url: function(title, callback) {
      if (!title) return callback(null);
      call_wikipedia_api(
        {action: "query", prop: "info", inprop: "url", titles: title },
        function(data) {
          var pages = data.query.pages;
          for (var p in pages) // Should only be 1 result
            return callback(p == "-1" ? null : pages[p].fullurl);
        }
      );
    },
    title_search: function(term, callback) {
      if (!term) return callback([]);
      call_wikipedia_api(
        { action: "opensearch", search: term },
        function(data) {
          callback(data[1]);
        }
      );
    },
    categories_for_title: function(title, callback) {
      if (!title) return callback(null);
      call_wikipedia_api(
        { action: "query", prop: "categories", cllimit: 500, titles: title },
        function(data) {
          var pages = data.query.pages;
          for (var p in pages)
            return callback(_.pluck(pages[p].categories, 'title'));
          return callback([]);
        }
      );
    },
    resolve_redirect: function(title, callback) {
      if (!title) return callback(null);
      call_wikipedia_api(
        { action: "query", redirects: "1", titles: title },
        function(data) {
          var redirects = data.query.redirects;
          if (redirects && redirects[0].from == title)
            callback(redirects[0].to);
        }
      );
    }
  };
})(window);