1 files changed, 13 insertions, 0 deletions
diff --git a/cli/js/headers.ts b/cli/js/headers.ts
index dc0de54dd..cc22077ad 100644
--- a/cli/js/headers.ts
+++ b/cli/js/headers.ts
@@ -2,6 +2,7 @@
 import * as domTypes from "./dom_types.ts";
 import { DomIterableMixin } from "./mixins/dom_iterable.ts";
 import { requiredArguments } from "./util.ts";
+import { customInspect } from "./console.ts";
 
 // From node-fetch
 // Copyright (c) 2016 David Frank. MIT License.
@@ -85,6 +86,18 @@ class HeadersBase {
     }
   }
 
+  [customInspect](): string {
+    let headerSize = this[headerMap].size;
+    let output = "";
+    this[headerMap].forEach((value, key) => {
+      const prefix = headerSize === this[headerMap].size ? " " : "";
+      const postfix = headerSize === 1 ? " " : ", ";
+      output = output + `${prefix}${key}: ${value}${postfix}`;
+      headerSize--;
+    });
+    return `Headers {${output}}`;
+  }
+
   // ref: https://fetch.spec.whatwg.org/#concept-headers-append
   append(name: string, value: string): void {
     requiredArguments("Headers.append", arguments.length, 2);