playwright: Implement basic defer() fn

Author: Turbo87

e2e/deferred.ts

@@ -0,0 +1,8 @@
+export function defer<T = undefined>(): { resolve: (any?) => T; reject: (reason: any) => void; promise: Promise<T> } {
+  let resolve, reject;
+  let promise = new Promise((res, rej) => {
+    resolve = res;
+    reject = rej;
+  }) as Promise<T>;
+  return { resolve, reject, promise };
+}