make sure a toast has not already been dismissed when dismissing it (e…

…lastic#868)

* make sure a toast has not already been dismissed when dismissing it

* changelog

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - `EuiButton`, `EuiButtonEmpty`, and `EuiButtonIcon` now look and behave disabled when `isDisabled={true}` ([#862](https://github.com/elastic/eui/pull/862))
 - `EuiGlobalToastList` no longer triggers `Uncaught TypeError: _this.callback is not a function`  ([#865](https://github.com/elastic/eui/pull/865))
+- `EuiGlobalToastList` checks to see if it has dismissed a toast before re-dismissing it ([#868](https://github.com/elastic/eui/pull/868))
 
 ## [`0.0.49`](https://github.com/elastic/eui/tree/v0.0.49)
 

src/components/toast/global_toast_list.js

@@ -108,18 +108,24 @@ export class EuiGlobalToastList extends Component {
   dismissToast = (toast) => {
     // Remove the toast after it's done fading out.
     this.dismissTimeoutIds.push(setTimeout(() => {
-      this.props.dismissToast(toast);
-      this.toastIdToTimerMap[toast.id].clear();
-      delete this.toastIdToTimerMap[toast.id];
-
-      this.setState(prevState => {
-        const toastIdToDismissedMap = { ...prevState.toastIdToDismissedMap };
-        delete toastIdToDismissedMap[toast.id];
-
-        return {
-          toastIdToDismissedMap,
-        };
-      });
+      // Because this is wrapped in a setTimeout, and because React does not guarantee when
+      // state updates happen, it is possible to double-dismiss a toast
+      // including by double-clicking the "x" button on the toast
+      // so, first check to make sure we haven't already dismissed this toast
+      if (this.toastIdToTimerMap.hasOwnProperty(toast.id)) {
+        this.props.dismissToast(toast);
+        this.toastIdToTimerMap[toast.id].clear();
+        delete this.toastIdToTimerMap[toast.id];
+
+        this.setState(prevState => {
+          const toastIdToDismissedMap = { ...prevState.toastIdToDismissedMap };
+          delete toastIdToDismissedMap[toast.id];
+
+          return {
+            toastIdToDismissedMap,
+          };
+        });
+      }
     }, TOAST_FADE_OUT_MS));
 
     this.setState(prevState => {