BREAKING CHANGE: Remove responseBody argument to header functions

Closes #1542

lib/request_overrider.js

@@ -474,15 +474,9 @@ function RequestOverrider(req, options, interceptors, remove, cb) {
 
       // Evaluate functional headers.
       const evaluatedHeaders = {}
-      Object.keys(response.headers).forEach(function(key) {
-        const value = response.headers[key]
-
+      Object.entries(response.headers).forEach(([key, value]) => {
         if (typeof value === 'function') {
-          response.headers[key] = evaluatedHeaders[key] = value(
-            req,
-            response,
-            responseBody
-          )
+          response.headers[key] = evaluatedHeaders[key] = value(req, response)
         }
       })
 

tests/test_reply_headers.js

@@ -66,21 +66,18 @@ test('reply header function is evaluated and the result sent in the mock respons
 })
 
 test('reply header function receives the correct arguments', async t => {
-  t.plan(4)
+  t.plan(3)
 
   const { ClientRequest: OverriddenClientRequest } = require('http')
   const scope = nock('http://example.test')
     .post('/')
     .reply(200, 'boo!', {
-      'X-My-Headers': (req, res, body) => {
+      'X-My-Headers': (req, res, ...rest) => {
         t.type(req, OverriddenClientRequest)
         t.type(res, IncomingMessage)
-        // TODO The current behavior is to pass the response body as a buffer.
-        // This doesn't seem at all helpful and seems like it is probably a
-        // bug.
+        // The third argument was once a buffer, though no longer.
         // https://github.com/nock/nock/issues/1542
-        t.type(body, Buffer)
-        t.true(Buffer.from('boo!').equals(body))
+        t.deepEqual(rest, [])
         return 'gotcha'
       },
     })