Only dispatch targetsUpdate events if the full editor is visible

We do not need these events when in fullscreen or player mode, and even if they do not change anything, the dispatch takes time.

This also re-requests a vm.emitTargetsUpdate when transitioning from fullscreen/player back to editor mode to make sure the most recent data is shown.

src/lib/vm-listener-hoc.jsx

@@ -23,7 +23,8 @@ const vmListenerHOC = function (WrappedComponent) {
             super(props);
             bindAll(this, [
                 'handleKeyDown',
-                'handleKeyUp'
+                'handleKeyUp',
+                'handleTargetsUpdate'
             ]);
             // We have to start listening to the vm here rather than in
             // componentDidMount because the HOC mounts the wrapped component,
@@ -31,7 +32,7 @@ const vmListenerHOC = function (WrappedComponent) {
             // mounts.
             // If the wrapped component uses the vm in componentDidMount, then
             // we need to start listening before mounting the wrapped component.
-            this.props.vm.on('targetsUpdate', this.props.onTargetsUpdate);
+            this.props.vm.on('targetsUpdate', this.handleTargetsUpdate);
             this.props.vm.on('MONITORS_UPDATE', this.props.onMonitorsUpdate);
             this.props.vm.on('BLOCK_DRAG_UPDATE', this.props.onBlockDragUpdate);
             this.props.vm.on('TURBO_MODE_ON', this.props.onTurboModeOn);
@@ -49,9 +50,15 @@ const vmListenerHOC = function (WrappedComponent) {
             }
             this.props.vm.postIOData('userData', {username: this.props.username});
         }
-        componentWillReceiveProps (newProps) {
-            if (newProps.username !== this.props.username) {
-                this.props.vm.postIOData('userData', {username: newProps.username});
+        componentDidUpdate (prevProps) {
+            if (prevProps.username !== this.props.username) {
+                this.props.vm.postIOData('userData', {username: this.props.username});
+            }
+
+            // Re-request a targets update when the shouldEmitTargetsUpdate state changes to true
+            // i.e. when the editor transitions out of fullscreen/player only modes
+            if (this.props.shouldEmitTargetsUpdate && !prevProps.shouldEmitTargetsUpdate) {
+                this.props.vm.emitTargetsUpdate();
             }
         }
         componentWillUnmount () {
@@ -61,6 +68,11 @@ const vmListenerHOC = function (WrappedComponent) {
                 document.removeEventListener('keyup', this.handleKeyUp);
             }
         }
+        handleTargetsUpdate (data) {
+            if (this.props.shouldEmitTargetsUpdate) {
+                this.props.onTargetsUpdate(data);
+            }
+        }
         handleKeyDown (e) {
             // Don't capture keys intended for Blockly inputs.
             if (e.target !== document && e.target !== document.body) return;
@@ -89,6 +101,7 @@ const vmListenerHOC = function (WrappedComponent) {
             const {
                 /* eslint-disable no-unused-vars */
                 attachKeyboardEvents,
+                shouldEmitTargetsUpdate,
                 username,
                 onBlockDragUpdate,
                 onKeyDown,
@@ -120,6 +133,7 @@ const vmListenerHOC = function (WrappedComponent) {
         onTargetsUpdate: PropTypes.func.isRequired,
         onTurboModeOff: PropTypes.func.isRequired,
         onTurboModeOn: PropTypes.func.isRequired,
+        shouldEmitTargetsUpdate: PropTypes.bool,
         username: PropTypes.string,
         vm: PropTypes.instanceOf(VM).isRequired
     };
@@ -127,6 +141,8 @@ const vmListenerHOC = function (WrappedComponent) {
         attachKeyboardEvents: true
     };
     const mapStateToProps = state => ({
+        // Do not emit target updates in fullscreen or player only mode
+        shouldEmitTargetsUpdate: !state.scratchGui.mode.isFullScreen && !state.scratchGui.mode.isPlayerOnly,
         vm: state.scratchGui.vm,
         username: state.session && state.session.session && state.session.session.user ?
             state.session.session.user.username : ''