1 files changed, 39 insertions, 0 deletions
diff --git a/src/promiseUtils.ts b/src/promiseUtils.ts
new file mode 100644
index 000000000..eb649471b
--- /dev/null
+++ b/src/promiseUtils.ts
@@ -0,0 +1,39 @@
+/*
+ This file is part of GNU Taler
+ (C) 2019 GNUnet e.V.
+
+ TALER is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+ export interface OpenedPromise<T> {
+  promise: Promise<T>;
+  resolve: (val: T) => void;
+  reject: (err: any) => void;
+ }
+
+/**
+ * Get an unresolved promise together with its extracted resolve / reject
+ * function.
+ */
+export function openPromise<T>(): OpenedPromise<T> {
+  let resolve: ((x?: any) => void) | null = null;
+  let reject: ((reason?: any) => void) | null = null;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  if (!(resolve && reject)) {
+    // Never happens, unless JS implementation is broken
+    throw Error();
+  }
+  return { resolve, reject, promise };
+}
+\ No newline at end of file