From 21acc9bd743da4e44b42c909abc3d2a3e36b4572 Mon Sep 17 00:00:00 2001
From: Gareth Jones <jones258@gmail.com>
Date: Sun, 6 Dec 2020 10:09:27 +1300
Subject: [PATCH] feat(typescript): make `verify` a type-guard

---
 src/verify/index.ts | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/verify/index.ts b/src/verify/index.ts
index e769a9d4..f3fd8000 100644
--- a/src/verify/index.ts
+++ b/src/verify/index.ts
@@ -1,7 +1,18 @@
 import { timingSafeEqual } from "crypto";
 import { Buffer } from "buffer";
+import { EventTypesPayload } from "../generated/get-webhook-payload-type-from-event";
 import { sign } from "../sign/index";
 
+type WebhookEvents = Exclude<
+  keyof EventTypesPayload,
+  `${string}.${string}` | "errors" | "*"
+>;
+
+type GithubEvent<TName extends WebhookEvents = WebhookEvents> = Omit<
+  EventTypesPayload[TName],
+  "name"
+> & { name: TName };
+
 const getAlgorithm = (signature: string) => {
   return signature.startsWith("sha256=") ? "sha256" : "sha1";
 };
@@ -10,7 +21,7 @@ export function verify(
   secret: string,
   eventPayload: object,
   signature: string
-): boolean {
+): eventPayload is GithubEvent {
   if (!secret || !eventPayload || !signature) {
     throw new TypeError(
       "[@octokit/webhooks] secret, eventPayload & signature required"