http: refactor to use validateHeaderName

Remove duplicate implementation by using validateHeaderName.

PR-URL: #46143
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

doc/api/http.md

@@ -3703,13 +3703,18 @@ Passing an `AbortSignal` and then calling `abort` on the corresponding
 `AbortController` will behave the same way as calling `.destroy()` on the
 request itself.
 
-## `http.validateHeaderName(name)`
+## `http.validateHeaderName(name[, label])`
 
 <!-- YAML
 added: v14.3.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/46143
+    description: The `label` parameter is added.
 -->
 
 * `name` {string}
+* `label` {string} Label for error message. **Default:** `'Header name'`.
 
 Performs the low-level validations on the provided `name` that are done when
 `res.setHeader(name, value)` is called.

lib/_http_outgoing.js

@@ -627,9 +627,9 @@ function matchHeader(self, state, field, value) {
   }
 }
 
-const validateHeaderName = hideStackFrames((name) => {
+const validateHeaderName = hideStackFrames((name, label) => {
   if (typeof name !== 'string' || !name || !checkIsHttpToken(name)) {
-    throw new ERR_INVALID_HTTP_TOKEN('Header name', name);
+    throw new ERR_INVALID_HTTP_TOKEN(label || 'Header name', name);
   }
 });
 
@@ -954,9 +954,7 @@ OutgoingMessage.prototype.addTrailers = function addTrailers(headers) {
       field = key;
       value = headers[key];
     }
-    if (typeof field !== 'string' || !field || !checkIsHttpToken(field)) {
-      throw new ERR_INVALID_HTTP_TOKEN('Trailer name', field);
-    }
+    validateHeaderName(field, 'Trailer name');
 
     // Check if the field must be sent several times
     const isArrayValue = ArrayIsArray(value);