1 files changed, 61 insertions, 0 deletions
diff --git a/devtools/client/debugger/src/actions/utils/middleware/promise.js b/devtools/client/debugger/src/actions/utils/middleware/promise.js
new file mode 100644
index 0000000000..52054a1fcc
--- /dev/null
+++ b/devtools/client/debugger/src/actions/utils/middleware/promise.js
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { executeSoon } from "../../../utils/DevToolsUtils";
+
+import { pending, rejected, fulfilled } from "../../../utils/async-value";
+export function asyncActionAsValue(action) {
+  if (action.status === "start") {
+    return pending();
+  }
+  if (action.status === "error") {
+    return rejected(action.error);
+  }
+  return fulfilled(action.value);
+}
+
+let seqIdVal = 1;
+
+function seqIdGen() {
+  return seqIdVal++;
+}
+
+function promiseMiddleware({ dispatch, getState }) {
+  return next => action => {
+    if (!(PROMISE in action)) {
+      return next(action);
+    }
+
+    const seqId = seqIdGen().toString();
+    const { [PROMISE]: promiseInst, ...originalActionProperties } = action;
+
+    // Create a new action that doesn't have the promise field and has
+    // the `seqId` field that represents the sequence id
+    action = { ...originalActionProperties, seqId };
+
+    dispatch({ ...action, status: "start" });
+
+    // Return the promise so action creators can still compose if they
+    // want to.
+    return Promise.resolve(promiseInst)
+      .finally(() => new Promise(resolve => executeSoon(resolve)))
+      .then(
+        value => {
+          dispatch({ ...action, status: "done", value: value });
+          return value;
+        },
+        error => {
+          dispatch({
+            ...action,
+            status: "error",
+            error: error.message || error,
+          });
+          return Promise.reject(error);
+        }
+      );
+  };
+}
+
+export const PROMISE = "@@dispatch/promise";
+export { promiseMiddleware as promise };