JavaScript标准编码风格

/*!
 * body-parser
 * Copyright(c) 2014-2015 Douglas Christopher Wilson
 * MIT Licensed
 */

'use strict'

/**
 * Module dependencies.
 * @private
 */

var deprecate = require('depd')('body-parser')

/**
 * Cache of loaded parsers.
 * @private
 */

var parsers = Object.create(null)

/**
 * @typedef Parsers
 * @type {function}
 * @property {function} json
 * @property {function} raw
 * @property {function} text
 * @property {function} urlencoded
 */

/**
 * Module exports.
 * @type {Parsers}
 */

exports = module.exports = deprecate.function(bodyParser,
  'bodyParser: use individual json/urlencoded middlewares')

/**
 * JSON parser.
 * @public
 */

Object.defineProperty(exports, 'json', {
  configurable: true,
  enumerable: true,
  get: createParserGetter('json')
})

/**
 * Raw parser.
 * @public
 */

Object.defineProperty(exports, 'raw', {
  configurable: true,
  enumerable: true,
  get: createParserGetter('raw')
})

/**
 * Text parser.
 * @public
 */

Object.defineProperty(exports, 'text', {
  configurable: true,
  enumerable: true,
  get: createParserGetter('text')
})

/**
 * URL-encoded parser.
 * @public
 */

Object.defineProperty(exports, 'urlencoded', {
  configurable: true,
  enumerable: true,
  get: createParserGetter('urlencoded')
})

/**
 * Create a middleware to parse json and urlencoded bodies.
 *
 * @param {object} [options]
 * @return {function}
 * @deprecated
 * @public
 */

function bodyParser (options) {
  var opts = {}

  // exclude type option
  if (options) {
    for (var prop in options) {
      if (prop !== 'type') {
        opts[prop] = options[prop]
      }
    }
  }

  var _urlencoded = exports.urlencoded(opts)
  var _json = exports.json(opts)

  return function bodyParser (req, res, next) {
    _json(req, res, function (err) {
      if (err) return next(err)
      _urlencoded(req, res, next)
    })
  }
}

/**
 * Create a getter for loading a parser.
 * @private
 */

function createParserGetter (name) {
  return function get () {
    return loadParser(name)
  }
}

/**
 * Load a parser module.
 * @private
 */

function loadParser (parserName) {
  var parser = parsers[parserName]

  if (parser !== undefined) {
    return parser
  }

  // this uses a switch for static require analysis
  switch (parserName) {
    case 'json':
      parser = require('./lib/types/json')
      break
    case 'raw':
      parser = require('./lib/types/raw')
      break
    case 'text':
      parser = require('./lib/types/text')
      break
    case 'urlencoded':
      parser = require('./lib/types/urlencoded')
      break
  }

  // store to prevent invoking require()
  return (parsers[parserName] = parser)
}