check if headers has been already sent in image middleware

CHANGELOG.md

@@ -30,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Improve `_outputFormatter` on cache catalog-response to prevent exception - @cewald (#432)
 - use ts for compiling additional scripts - @gibkigonzo (#437)
 - Bugfix for wrong JSON scheme url's and hostname resolution for `magento1` platform - @cewald (#443)
+- check if headers has been already sent in image middleware - @gibkigonzo (#434)
 
 ## [1.11.1] - 2020.03.17
 

src/api/img.ts

@@ -41,6 +41,10 @@ export default ({ config, db }) =>
       imageBuffer = imageAction.imageBuffer
     }
 
+    if (res.headersSent) {
+      return
+    }
+
     return res
       .type(imageAction.mimeType)
       .set({ 'Cache-Control': `max-age=${imageAction.maxAgeForResponse}` })