From 99b4654fb8c707d4bc06d9c3e1a81fbf5c0f49f8 Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tasn@users.noreply.github.com>
Date: Thu, 29 Jun 2023 11:08:56 -0400
Subject: [PATCH] JavaScript: Add an explicit check that payload is a string
 (#978)

We had a check in typescript, but this obviously doesn't matter in
JavaScript environments. Passing an object instead of a payload is an
extremely common error case, so it's better to be explicit about it
rather than implicit (just failing verification).

Fixes #977
---
 javascript/src/index.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/javascript/src/index.ts b/javascript/src/index.ts
index 6b93adddc..69f5213a8 100644
--- a/javascript/src/index.ts
+++ b/javascript/src/index.ts
@@ -768,6 +768,10 @@ export class Webhook {
       | WebhookUnbrandedRequiredHeaders
       | Record<string, string>
   ): unknown {
+    if (typeof payload !== "string") {
+      throw new Error("Expected payload to be of type string. Please refer to https://docs.svix.com/receiving/verifying-payloads/how for more information.");
+    }
+
     const headers: Record<string, string> = {};
     for (const key of Object.keys(headers_)) {
       headers[key.toLowerCase()] = (headers_ as Record<string, string>)[key];