From b40c2a95084da694512c46a745c20c7d1e3e2c92 Mon Sep 17 00:00:00 2001
From: HenryNguyen5 <ngu.henry@hotmail.com>
Date: Mon, 21 May 2018 14:39:03 -0400
Subject: [PATCH] TS Improvements (#1676)

* Do not truncate errors, pretty output

* Introduce helpers for sagas

* Update yarn lock
---
 shared/types/sagaHelpers.d.ts | 22 ++++++++++++++++++++++
 tsconfig.json                 |  2 ++
 2 files changed, 24 insertions(+)
 create mode 100644 shared/types/sagaHelpers.d.ts

diff --git a/shared/types/sagaHelpers.d.ts b/shared/types/sagaHelpers.d.ts
new file mode 100644
index 00000000..812a869d
--- /dev/null
+++ b/shared/types/sagaHelpers.d.ts
@@ -0,0 +1,22 @@
+import { Effect } from 'redux-saga/effects';
+
+type ExtPromise<T> = T extends Promise<infer U> ? U : T;
+
+type ExtSaga<T> = T extends IterableIterator<infer U> ? Exclude<U, Effect | Effect[]> : T;
+
+/**
+ * Use this helper to unwrap return types from effects like Call / Apply
+ * In the case of calling a function that returns a promise, this helper will unwrap the
+ * promise and return the type inside it. In the case of calling another saga / generator,
+ * this helper will return the actual return value of the saga / generator, otherwise,
+ * it'll return the original type.
+ *
+ * NOTE 1: When using this to extract the type of a Saga, make sure to remove the `SagaIterator`
+ * return type of the saga if it contains one, since that masks the actual return type of the saga.
+ *
+ * NOTE 2: You will most likely need to use the `typeof` operator to use this helper.
+ * E.g type X = UnwrapEffects<typeof MyFunc/MySaga>
+ */
+export type UnwrapEffects<T> = T extends (...args: any[]) => any
+  ? ExtSaga<ReturnType<T>>
+  : ExtPromise<T>;
diff --git a/tsconfig.json b/tsconfig.json
index f878f0a4..11fd0130 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -18,6 +18,8 @@
     "noEmitOnError": false,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
+    "pretty": true,
+    "noErrorTruncation": true,
     "noImplicitAny": true
   },
   "include": [