frontend: utils: add defered pattern

Author: nicoschmdt

core/frontend/src/utils/deferred.ts

@@ -0,0 +1,15 @@
+interface Deferred<T> {
+  promise: Promise<T>
+  resolve: (value: T) => void
+  reject: (reason: Error) => void
+}
+  
+export function createDeferred<T>(): Deferred<T> {
+  let resolve!: (value: T) => void
+  let reject!: (reason: Error) => void
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res
+    reject = rej
+  })
+  return { promise, resolve, reject }
+}