Also use the qs module for the simple parser (expressjs#387)

* Always use the qs module, even in simple mode

expressjs#326 (comment)

* Create the simple and extended parser with the same function, reducing duplication

* Don't mention the querystring module in the README

* Fix lint

README.md

@@ -228,12 +228,10 @@ any of the following keys:
 
 ##### extended
 
-The `extended` option allows to choose between parsing the URL-encoded data
-with the `querystring` library (when `false`) or the `qs` library (when
-`true`). The "extended" syntax allows for rich objects and arrays to be
-encoded into the URL-encoded format, allowing for a JSON-like experience
-with URL-encoded. For more information, please
-[see the qs library](https://www.npmjs.org/package/qs#readme).
+The "extended" syntax allows for rich objects and arrays to be encoded into the
+URL-encoded format, allowing for a JSON-like experience with URL-encoded. For
+more information, please [see the qs
+library](https://www.npmjs.org/package/qs#readme).
 
 Defaults to `false`.
 

lib/types/urlencoded.js

@@ -19,19 +19,14 @@ var debug = require('debug')('body-parser:urlencoded')
 var isFinished = require('on-finished').isFinished
 var read = require('../read')
 var typeis = require('type-is')
+var qs = require('qs')
 
 /**
  * Module exports.
  */
 
 module.exports = urlencoded
 
-/**
- * Cache of parser modules.
- */
-
-var parsers = Object.create(null)
-
 /**
  * Create a middleware to parse urlencoded bodies.
  *
@@ -56,9 +51,7 @@ function urlencoded (options) {
   }
 
   // create the appropriate query parser
-  var queryparse = extended
-    ? extendedparser(opts)
-    : simpleparser(opts)
+  var queryparse = createQueryParser(opts, extended)
 
   // create the appropriate type checking function
   var shouldParse = typeof type !== 'function'
@@ -126,11 +119,10 @@ function urlencoded (options) {
  * @param {object} options
  */
 
-function extendedparser (options) {
+function createQueryParser (options, extended) {
   var parameterLimit = options.parameterLimit !== undefined
     ? options.parameterLimit
     : 1000
-  var parse = parser('qs')
 
   if (isNaN(parameterLimit) || parameterLimit < 1) {
     throw new TypeError('option parameterLimit must be a positive number')
@@ -140,6 +132,8 @@ function extendedparser (options) {
     parameterLimit = parameterLimit | 0
   }
 
+  var depth = extended ? Infinity : 0
+
   return function queryparse (body) {
     var paramCount = parameterCount(body, parameterLimit)
 
@@ -150,13 +144,14 @@ function extendedparser (options) {
       })
     }
 
-    var arrayLimit = Math.max(100, paramCount)
+    var arrayLimit = extended ? Math.max(100, paramCount) : 0
+
+    debug('parse ' + (extended ? 'extended ' : '') + 'urlencoding')
 
-    debug('parse extended urlencoding')
-    return parse(body, {
+    return qs.parse(body, {
       allowPrototypes: true,
       arrayLimit: arrayLimit,
-      depth: Infinity,
+      depth: depth,
       parameterLimit: parameterLimit
     })
   }
@@ -201,72 +196,6 @@ function parameterCount (body, limit) {
   return count
 }
 
-/**
- * Get parser for module name dynamically.
- *
- * @param {string} name
- * @return {function}
- * @api private
- */
-
-function parser (name) {
-  var mod = parsers[name]
-
-  if (mod !== undefined) {
-    return mod.parse
-  }
-
-  // this uses a switch for static require analysis
-  switch (name) {
-    case 'qs':
-      mod = require('qs')
-      break
-    case 'querystring':
-      mod = require('querystring')
-      break
-  }
-
-  // store to prevent invoking require()
-  parsers[name] = mod
-
-  return mod.parse
-}
-
-/**
- * Get the simple query parser.
- *
- * @param {object} options
- */
-
-function simpleparser (options) {
-  var parameterLimit = options.parameterLimit !== undefined
-    ? options.parameterLimit
-    : 1000
-  var parse = parser('querystring')
-
-  if (isNaN(parameterLimit) || parameterLimit < 1) {
-    throw new TypeError('option parameterLimit must be a positive number')
-  }
-
-  if (isFinite(parameterLimit)) {
-    parameterLimit = parameterLimit | 0
-  }
-
-  return function queryparse (body) {
-    var paramCount = parameterCount(body, parameterLimit)
-
-    if (paramCount === undefined) {
-      debug('too many parameters')
-      throw createError(413, 'too many parameters', {
-        type: 'parameters.too.many'
-      })
-    }
-
-    debug('parse urlencoding')
-    return parse(body, undefined, undefined, { maxKeys: parameterLimit })
-  }
-}
-
 /**
  * Get the simple type checker.
  *