diff --git a/README.md b/README.md
index 394d577c..f80f0b47 100644
--- a/README.md
+++ b/README.md
@@ -91,7 +91,7 @@ to `'100kb'`.
 ##### parser
 
 The `parser` option is the function called against the request body to convert
-it to a Javascript object. If a `reviver` is supplied, it is supplied as the
+it to a JavaScript object. If a `reviver` is supplied, it is supplied as the
 second argument to this function.
 
 ```
@@ -309,7 +309,7 @@ The `depth` option is used to configure the maximum depth of the `qs` library wh
 ##### parser
 
 The `parser` option, if supplied, is used to in place of the default parser to
-convert the request body into a Javascript object. If this option is supplied,
+convert the request body into a JavaScript object. If this option is supplied,
 both the `extended` and `parameterLimit` options are ignored.
 
 ```
diff --git a/lib/generic-parser.js b/lib/factory.js
similarity index 90%
rename from lib/generic-parser.js
rename to lib/factory.js
index deb96d10..5f04ab7a 100644
--- a/lib/generic-parser.js
+++ b/lib/factory.js
@@ -24,20 +24,21 @@ var typeis = require('type-is')
  * Module exports.
  */
 
-module.exports = generic
+module.exports = createBodyParser
 
 /**
  * Use this to create a middleware that parses request bodies
  *
- * @param {object} [options]
+ * @param {function} parse
+ * @param {object} options
+ * @param {object} defaultOptions
  * @return {function}
  * @public
  */
 
-function generic (parserOptions, parserOverrides) {
+function createBodyParser (parse, options, defaultOptions) {
   // Squash the options and the overrides down into one object
-  var opts = Object.create(parserOptions)
-  Object.assign(opts, parserOverrides)
+  var opts = { ...defaultOptions || {}, ...options }
 
   var limit = typeof opts.limit !== 'number'
     ? bytes.parse(opts.limit || '100kb')
@@ -45,7 +46,6 @@ function generic (parserOptions, parserOverrides) {
   var charset = opts.charset
   var inflate = opts.inflate !== false
   var verify = opts.verify || false
-  var parse = opts.parse || defaultParse
   var defaultReqCharset = opts.defaultCharset || 'utf-8'
   var type = opts.type
 
@@ -63,7 +63,7 @@ function generic (parserOptions, parserOverrides) {
     ? charsetValidator(charset)
     : charset
 
-  return function genericParser (req, res, next) {
+  return function (req, res, next) {
     if (isFinished(req)) {
       debug('body already parsed')
       next()
@@ -114,10 +114,6 @@ function generic (parserOptions, parserOverrides) {
   }
 }
 
-function defaultParse (buf) {
-  return buf
-}
-
 /**
  * Get the charset of a request.
  *
diff --git a/lib/types/json.js b/lib/types/json.js
index ae1af796..44725fd1 100644
--- a/lib/types/json.js
+++ b/lib/types/json.js
@@ -12,7 +12,7 @@
  * @private
  */
 
-var genericParser = require('../..').generic
+var createBodyParser = require('../factory')
 var debug = require('debug')('body-parser:json')
 
 /**
@@ -52,16 +52,9 @@ function json (options) {
   var reviver = opts.reviver
   var strict = opts.strict !== false
   var parser = opts.parser || JSON.parse
-  var type = opts.type || 'application/json'
 
-  return genericParser(opts, {
-    type: type,
-
-    charset: function validateCharset (charset) {
-      return charset.slice(0, 4) === 'utf-'
-    },
-
-    parse: function parse (buf) {
+  return createBodyParser(
+    function (buf) {
       if (buf.length === 0) {
         // special-case empty json body, as it's a common client-side mistake
         // TODO: maybe make this configurable or part of "strict" option
@@ -86,8 +79,16 @@ function json (options) {
           stack: e.stack
         })
       }
+    },
+    opts,
+    {
+      parser: JSON.parse,
+      type: 'application/json',
+      charset: function (charset) {
+        return charset.slice(0, 4) === 'utf-'
+      }
     }
-  })
+  )
 }
 
 /**
diff --git a/lib/types/raw.js b/lib/types/raw.js
index b40cfd5d..3a33e888 100644
--- a/lib/types/raw.js
+++ b/lib/types/raw.js
@@ -10,7 +10,7 @@
  * Module dependencies.
  */
 
-var genericParser = require('../..').generic
+var createBodyParser = require('../factory')
 
 /**
  * Module exports.
@@ -27,11 +27,11 @@ module.exports = raw
  */
 
 function raw (options) {
-  var opts = options || {}
-
-  var type = opts.type || 'application/octet-stream'
-
-  return genericParser(opts, {
-    type: type
-  })
+  return createBodyParser(
+    function (buf) { return buf },
+    options,
+    {
+      type: 'application/octet-stream'
+    }
+  )
 }
diff --git a/lib/types/text.js b/lib/types/text.js
index 87e65793..2b8ef4ec 100644
--- a/lib/types/text.js
+++ b/lib/types/text.js
@@ -10,7 +10,7 @@
  * Module dependencies.
  */
 
-var genericParser = require('../..').generic
+var createBodyParser = require('../factory')
 
 /**
  * Module exports.
@@ -27,14 +27,13 @@ module.exports = text
  */
 
 function text (options) {
-  var opts = options || {}
-
-  var defaultCharset = opts.defaultCharset || 'utf-8'
-  var type = opts.type || 'text/plain'
-
-  return genericParser(opts, {
-    type: type,
-    charset: function validateCharset () { return true },
-    defaultCharset: defaultCharset
-  })
+  return createBodyParser(
+    function (buf) { return buf },
+    options,
+    {
+      type: 'text/plain',
+      charset: function () { return true },
+      defaultCharset: 'utf-8'
+    }
+  )
 }
diff --git a/lib/types/urlencoded.js b/lib/types/urlencoded.js
index 95520a26..cd93f149 100644
--- a/lib/types/urlencoded.js
+++ b/lib/types/urlencoded.js
@@ -14,7 +14,7 @@
 
 var createError = require('http-errors')
 var debug = require('debug')('body-parser:urlencoded')
-var genericParser = require('../..').generic
+var createBodyParser = require('../factory')
 var qs = require('qs')
 
 /**
@@ -34,23 +34,21 @@ function urlencoded (options) {
   var opts = options || {}
 
   var extended = Boolean(opts.extended)
-  var type = opts.type || 'application/x-www-form-urlencoded'
 
   var queryparse = opts.parser || createQueryParser(opts, extended)
 
-  return genericParser(opts, {
-    type: type,
-
-    charset: function validateCharset (charset) {
-      return charset === 'utf-8' || charset === 'iso-8859-1'
+  return createBodyParser(
+    function (body, encoding) {
+      return body.length ? queryparse(body, encoding) : {}
     },
-
-    parse: function parse (body, encoding) {
-      return body.length
-        ? queryparse(body, encoding)
-        : {}
+    opts,
+    {
+      type: 'application/x-www-form-urlencoded',
+      charset: function (charset) {
+        return charset === 'utf-8' || charset === 'iso-8859-1'
+      }
     }
-  })
+  )
 }
 
 /**