fix: 🐛 add custom headers to subscription in apollo client (#11744)

Co-authored-by: Tobbe Lundberg <tobbe@tlundberg.com>

.changesets/11744.md

@@ -0,0 +1,3 @@
+- fix: :bug: add custom headers to subscription in apollo client (#11744) by @dennemark
+
+Allow passing custom headers to `sseLink`, which is used by the Apollo client for subscriptions.

packages/web/src/apollo/sseLink.ts

@@ -95,22 +95,21 @@ class SSELink extends ApolloLink {
     super()
 
     const { url, auth, headers, httpLinkConfig } = options
-    const { credentials, referrer, referrerPolicy } =
+    const { credentials, referrer, referrerPolicy, ...customHeaders } =
       httpLinkConfig?.headers || {}
 
     this.client = createClient({
       url,
       headers: async () => {
         const token = await auth.tokenFn()
 
-        // Only add auth headers when there's a token. `token` is `null` when `!isAuthenticated`.
-        if (!token) {
-          return { ...headers }
-        }
+        // Only add auth headers when there's a token. `token` is `null` when
+        // `!isAuthenticated`.
         return {
-          Authorization: `Bearer ${token}`,
-          'auth-provider': auth.authProviderType,
+          ...(token && { Authorization: `Bearer ${token}` }),
+          ...(token && { 'auth-provider': auth.authProviderType }),
           ...headers,
+          ...customHeaders,
         }
       },
       credentials: mapCredentialsHeader(credentials),