feat(headers): allow headers to be array per new undici behavior

.trunk/.gitignore

@@ -6,3 +6,4 @@
 plugins
 user_trunk.yaml
 user.yaml
+tmp

.trunk/trunk.yaml

@@ -2,11 +2,11 @@
 # To learn more about the format of this file, see https://docs.trunk.io/reference/trunk-yaml
 version: 0.1
 cli:
-  version: 1.17.2
+  version: 1.21.0
 plugins:
   sources:
     - id: trunk
-      ref: v1.2.6
+      ref: v1.4.5
       uri: https://github.com/trunk-io/plugins
 runtimes:
   enabled:
@@ -15,18 +15,18 @@ runtimes:
     - python@3.10.8
 lint:
   enabled:
-    - actionlint@1.6.26
-    - checkov@3.0.29
-    - eslint@8.53.0
+    - actionlint@1.6.27
+    - checkov@3.2.53
+    - eslint@8.57.0
     - git-diff-check
-    - markdownlint@0.37.0
-    - osv-scanner@1.4.3
-    - prettier@3.0.3
-    - shellcheck@0.9.0
+    - markdownlint@0.39.0
+    - osv-scanner@1.7.0
+    - prettier@3.2.5
+    - shellcheck@0.10.0
     - shfmt@3.6.0
-    - trivy@0.47.0
-    - trufflehog@3.62.1
-    - yamllint@1.32.0
+    - trivy@0.50.1
+    - trufflehog@3.71.0
+    - yamllint@1.35.1
   ignore:
     - linters: [ALL]
       paths:

src/index.ts

@@ -34,7 +34,7 @@ interface FetchRequest {
   method: string;
   origin: string;
   path: string;
-  headers: string;
+  headers: string | string[];
 }
 
 interface FetchResponse {
@@ -179,9 +179,13 @@ export class FetchInstrumentation implements Instrumentation {
       this.config.onRequest({ request, span, additionalHeaders: addedHeaders });
     }
 
-    request.headers += Object.entries(addedHeaders)
-      .map(([k, v]) => `${k}: ${v}\r\n`)
-      .join('');
+    if (Array.isArray(request.headers)) {
+      request.headers.push(...Object.entries(addedHeaders).flat());
+    } else {
+      request.headers += Object.entries(addedHeaders)
+        .map(([k, v]) => `${k}: ${v}\r\n`)
+        .join('');
+    }
     this.spanFromReq.set(request, span);
   }