pkg/browser/lib/dart.js

// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

(function() {
// Bootstrap support for Dart scripts on the page as this script.
// TODO(18463): Remove user agent check. We will remove 'Dart' from there.
if (!navigator.dartEnabled && (navigator.userAgent.indexOf('(Dart)') === -1)) {
  // TODO:
  // - Support in-browser compilation.
  // - Handle inline Dart scripts.

  // Fall back to compiled JS. Run through all the scripts and
  // replace them if they have a type that indicate that they source
  // in Dart code (type="application/dart").
  var scripts = document.getElementsByTagName("script");
  var length = scripts.length;
  for (var i = 0; i < length; ++i) {
    if (scripts[i].type == "application/dart") {
      // Remap foo.dart to foo.dart.js.
      if (scripts[i].src && scripts[i].src != '') {
        var script = document.createElement('script');
        script.src = scripts[i].src.replace(/\.dart(?=\?|$)/, '.dart.js');
        var parent = scripts[i].parentNode;
        // TODO(vsm): Find a solution for issue 8455 that works with more
        // than one script.
        document.currentScript = script;
        parent.replaceChild(script, scripts[i]);

        // Support for incremental compilation.
        script.onload = function (event) {
          var script = event.target;
          if (self.$dart_unsafe_incremental_support) {
            new WebSocket(script.src.replace(/^http/, 'ws')).onmessage =
              function (event) {
                var patch = String(event.data);
                self.$dart_unsafe_incremental_support.patch(patch);
                script.dispatchEvent(
                  new CustomEvent(
                    "dart_program_updated",
                    { bubbles: true, detail: { patch: patch } }));
              };
          }
        };
      }
    }
  }
}
})();