Dev mode loader for webcomponentsjs-lite.js

webcomponents-lite.js

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+/*
+ * Copyright 2013 The Polymer Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ */
+
+(function() {
+
+  // Establish scope.
+  window.WebComponents = window.WebComponents || {flags:{}};
+
+  // loading script
+  var file = 'webcomponents-lite.js';
+  var script = document.querySelector('script[src*="' + file + '"]');
+
+  // Flags. Convert url arguments to flags
+  var flags = {};
+  if (!flags.noOpts) {
+    // from url
+    location.search.slice(1).split('&').forEach(function(o) {
+      o = o.split('=');
+      o[0] && (flags[o[0]] = o[1] || true);
+    });
+    // from script
+    if (script) {
+      for (var i=0, a; (a=script.attributes[i]); i++) {
+        if (a.name !== 'src') {
+          flags[a.name] = a.value || true;
+        }
+      }
+    }
+    // log flags
+    if (flags.log) {
+      var parts = flags.log.split(',');
+      flags.log = {};
+      parts.forEach(function(f) {
+        flags.log[f] = true;
+      });
+    } else {
+      flags.log = {};
+    }
+  }
+
+  // Determine default settings.
+  // If any of these flags match 'native', then force native ShadowDOM; any
+  // other truthy value, or failure to detect native
+  // ShadowDOM, results in polyfill
+  flags.shadow = (flags.shadow || flags.shadowdom || flags.polyfill);
+  if (flags.shadow === 'native') {
+    flags.shadow = false;
+  } else {
+    flags.shadow = flags.shadow || !HTMLElement.prototype.createShadowRoot;
+  }
+
+  // construct full dependency list
+  var modules = [
+    'HTMLImports/HTMLImports.js',
+    'CustomElements/CustomElements.js',
+    // these scripts are loaded here due to polyfill timing issues
+    'WebComponents/unresolved.js'
+  ];
+
+  var src = script.getAttribute('src');
+  var path = src.slice(0, src.lastIndexOf(file));
+
+  modules.forEach(function(f) {
+    document.write('<script src="' + path + 'src/' + f + '"></script>');
+  });
+
+  // exports
+  WebComponents.flags = flags;
+
+})();