Fix bug in FB button component & simplify injectHead util

js/components/ascribe_buttons/acl_button_list.js

@@ -41,7 +41,7 @@ let AclButtonList = React.createClass({
 
     componentDidMount() {
         UserStore.listen(this.onChange);
-        UserActions.fetchCurrentUser();
+        UserActions.fetchCurrentUser.defer();
 
         window.addEventListener('resize', this.handleResize);
         window.dispatchEvent(new Event('resize'));

js/components/ascribe_social_share/facebook_share_button.js

@@ -8,7 +8,6 @@ import { InjectInHeadUtils } from '../../utils/inject_utils';
 
 let FacebookShareButton = React.createClass({
     propTypes: {
-        url: React.PropTypes.string,
         type: React.PropTypes.string
     },
 
@@ -28,12 +27,14 @@ let FacebookShareButton = React.createClass({
          * To circumvent this, we always have the sdk parse the entire DOM on the initial load
          * (see FacebookHandler) and then use FB.XFBML.parse() on the mounting component later.
          */
-        if (!InjectInHeadUtils.isPresent('script', AppConstants.facebook.sdkUrl)) {
-            InjectInHeadUtils.inject(AppConstants.facebook.sdkUrl);
-        } else {
-            // Parse() searches the children of the element we give it, not the element itself.
-            FB.XFBML.parse(this.refs.fbShareButton.getDOMNode().parentElement);
-        }
+
+        InjectInHeadUtils
+            .inject(AppConstants.facebook.sdkUrl)
+            .then(() => { FB.XFBML.parse(this.refs.fbShareButton.getDOMNode().parentElement) });
+    },
+
+    shouldComponentUpdate(nextProps) {
+        return this.props.type !== nextProps.type;
     },
 
     render() {
@@ -41,7 +42,6 @@ let FacebookShareButton = React.createClass({
             <span
                 ref="fbShareButton"
                 className="fb-share-button btn btn-ascribe-social"
-                data-href={this.props.url}
                 data-layout={this.props.type}>
             </span>
         );

js/utils/inject_utils.js

@@ -12,16 +12,16 @@ let mapTag = {
     css: 'link'
 };
 
+let tags = {};
+
 function injectTag(tag, src) {
-    return Q.Promise((resolve, reject) => {
-        if (isPresent(tag, src)) {
-            resolve();
-        } else {
+    if(!tags[src]) {
+        tags[src] = Q.Promise((resolve, reject) => {
             let attr = mapAttr[tag];
             let element = document.createElement(tag);
             if (tag === 'script') {
-                element.onload = () => resolve();
-                element.onerror = () => reject();
+                element.onload = resolve;
+                element.onerror = reject;
             } else {
                 resolve();
             }
@@ -30,14 +30,10 @@ function injectTag(tag, src) {
             if (tag === 'link') {
                 element.rel = 'stylesheet';
             }
-        }
-    });
-}
+        });
+    }
 
-function isPresent(tag, src) {
-    let attr = mapAttr[tag];
-    let query = `head > ${tag}[${attr}="${src}"]`;
-    return document.querySelector(query);
+    return tags[src];
 }
 
 function injectStylesheet(src) {
@@ -65,7 +61,6 @@ export const InjectInHeadUtils = {
      * you don't want to embed everything inside the build file.
      */
 
-    isPresent,
     injectStylesheet,
     injectScript,
     inject