refactor: switch to const/let and enable eslint no-var rule

.eslintrc.yml

@@ -9,3 +9,4 @@ overrides:
     processor: 'markdown/markdown'
 rules:
   no-param-reassign: error
+  no-var: error

lib/read.js

@@ -11,13 +11,13 @@
  * @private
  */
 
-var createError = require('http-errors')
-var getBody = require('raw-body')
-var iconv = require('iconv-lite')
-var onFinished = require('on-finished')
-var zlib = require('node:zlib')
-var hasBody = require('type-is').hasBody
-var { getCharset } = require('./utils')
+const createError = require('http-errors')
+const getBody = require('raw-body')
+const iconv = require('iconv-lite')
+const onFinished = require('on-finished')
+const zlib = require('node:zlib')
+const hasBody = require('type-is').hasBody
+const { getCharset } = require('./utils')
 
 /**
  * Module exports.
@@ -63,7 +63,7 @@ function read (req, res, next, parse, debug, options) {
     return
   }
 
-  var encoding = null
+  let encoding = null
   if (options?.skipCharset !== true) {
     encoding = getCharset(req) || options.defaultCharset
 
@@ -78,12 +78,12 @@ function read (req, res, next, parse, debug, options) {
     }
   }
 
-  var length
-  var opts = options
-  var stream
+  let length
+  const opts = options
+  let stream
 
   // read options
-  var verify = opts.verify
+  const verify = opts.verify
 
   try {
     // get the content stream
@@ -112,7 +112,7 @@ function read (req, res, next, parse, debug, options) {
   debug('read body')
   getBody(stream, opts, function (error, body) {
     if (error) {
-      var _error
+      let _error
 
       if (error.type === 'encoding.unsupported') {
         // echo back charset
@@ -153,7 +153,7 @@ function read (req, res, next, parse, debug, options) {
     }
 
     // parse
-    var str = body
+    let str = body
     try {
       debug('parse body')
       str = typeof body !== 'string' && encoding !== null
@@ -182,8 +182,8 @@ function read (req, res, next, parse, debug, options) {
  * @private
  */
 function contentstream (req, debug, inflate) {
-  var encoding = (req.headers['content-encoding'] || 'identity').toLowerCase()
-  var length = req.headers['content-length']
+  const encoding = (req.headers['content-encoding'] || 'identity').toLowerCase()
+  const length = req.headers['content-length']
 
   debug('content-encoding "%s"', encoding)
 
@@ -199,7 +199,7 @@ function contentstream (req, debug, inflate) {
     return req
   }
 
-  var stream = createDecompressionStream(encoding, debug)
+  const stream = createDecompressionStream(encoding, debug)
   req.pipe(stream)
   return stream
 }

lib/types/json.js

@@ -12,9 +12,9 @@
  * @private
  */
 
-var debug = require('debug')('body-parser:json')
-var read = require('../read')
-var { normalizeOptions } = require('../utils')
+const debug = require('debug')('body-parser:json')
+const read = require('../read')
+const { normalizeOptions } = require('../utils')
 
 /**
  * Module exports.
@@ -33,10 +33,10 @@ module.exports = json
  *            %x0A /              ; Line feed or New line
  *            %x0D )              ; Carriage return
  */
-var FIRST_CHAR_REGEXP = /^[\x20\x09\x0a\x0d]*([^\x20\x09\x0a\x0d])/ // eslint-disable-line no-control-regex
+const FIRST_CHAR_REGEXP = /^[\x20\x09\x0a\x0d]*([^\x20\x09\x0a\x0d])/ // eslint-disable-line no-control-regex
 
-var JSON_SYNTAX_CHAR = '#'
-var JSON_SYNTAX_REGEXP = /#+/g
+const JSON_SYNTAX_CHAR = '#'
+const JSON_SYNTAX_REGEXP = /#+/g
 
 /**
  * Create a middleware to parse JSON bodies.
@@ -126,8 +126,8 @@ function createJsonParser (options) {
  * @private
  */
 function createStrictSyntaxError (str, char) {
-  var index = str.indexOf(char)
-  var partial = ''
+  const index = str.indexOf(char)
+  let partial = ''
 
   if (index !== -1) {
     partial = str.substring(0, index) + JSON_SYNTAX_CHAR.repeat(str.length - index)
@@ -153,7 +153,7 @@ function createStrictSyntaxError (str, char) {
  * @private
  */
 function firstchar (str) {
-  var match = FIRST_CHAR_REGEXP.exec(str)
+  const match = FIRST_CHAR_REGEXP.exec(str)
 
   return match
     ? match[1]
@@ -169,10 +169,10 @@ function firstchar (str) {
  * @private
  */
 function normalizeJsonSyntaxError (error, obj) {
-  var keys = Object.getOwnPropertyNames(error)
+  const keys = Object.getOwnPropertyNames(error)
 
-  for (var i = 0; i < keys.length; i++) {
-    var key = keys[i]
+  for (let i = 0; i < keys.length; i++) {
+    const key = keys[i]
     if (key !== 'stack' && key !== 'message') {
       delete error[key]
     }

lib/types/raw.js

@@ -10,9 +10,9 @@
  * Module dependencies.
  */
 
-var debug = require('debug')('body-parser:raw')
-var read = require('../read')
-var { normalizeOptions, passthrough } = require('../utils')
+const debug = require('debug')('body-parser:raw')
+const read = require('../read')
+const { normalizeOptions, passthrough } = require('../utils')
 
 /**
  * Module exports.

lib/types/text.js

@@ -10,9 +10,9 @@
  * Module dependencies.
  */
 
-var debug = require('debug')('body-parser:text')
-var read = require('../read')
-var { normalizeOptions, passthrough } = require('../utils')
+const debug = require('debug')('body-parser:text')
+const read = require('../read')
+const { normalizeOptions, passthrough } = require('../utils')
 
 /**
  * Module exports.

lib/types/urlencoded.js

@@ -12,11 +12,11 @@
  * @private
  */
 
-var createError = require('http-errors')
-var debug = require('debug')('body-parser:urlencoded')
-var read = require('../read')
-var qs = require('qs')
-var { normalizeOptions } = require('../utils')
+const createError = require('http-errors')
+const debug = require('debug')('body-parser:urlencoded')
+const read = require('../read')
+const qs = require('qs')
+const { normalizeOptions } = require('../utils')
 
 /**
  * Module exports.
@@ -60,13 +60,13 @@ function urlencoded (options) {
  * @private
  */
 function createQueryParser (options) {
-  var extended = Boolean(options?.extended)
-  var parameterLimit = options?.parameterLimit !== undefined
+  const extended = Boolean(options?.extended)
+  let parameterLimit = options?.parameterLimit !== undefined
     ? options?.parameterLimit
     : 1000
-  var charsetSentinel = options?.charsetSentinel
-  var interpretNumericEntities = options?.interpretNumericEntities
-  var depth = extended ? (options?.depth !== undefined ? options?.depth : 32) : 0
+  const charsetSentinel = options?.charsetSentinel
+  const interpretNumericEntities = options?.interpretNumericEntities
+  const depth = extended ? (options?.depth !== undefined ? options?.depth : 32) : 0
 
   if (isNaN(parameterLimit) || parameterLimit < 1) {
     throw new TypeError('option parameterLimit must be a positive number')
@@ -83,7 +83,7 @@ function createQueryParser (options) {
   return function parse (body, encoding) {
     if (!body.length) return {}
 
-    var paramCount = parameterCount(body, parameterLimit)
+    const paramCount = parameterCount(body, parameterLimit)
 
     if (paramCount === undefined) {
       debug('too many parameters')
@@ -92,7 +92,7 @@ function createQueryParser (options) {
       })
     }
 
-    var arrayLimit = extended ? Math.max(100, paramCount) : paramCount
+    const arrayLimit = extended ? Math.max(100, paramCount) : paramCount
 
     debug('parse ' + (extended ? 'extended ' : '') + 'urlencoding')
     try {

lib/utils.js

@@ -4,9 +4,9 @@
  * Module dependencies.
  */
 
-var bytes = require('bytes')
-var contentType = require('content-type')
-var typeis = require('type-is')
+const bytes = require('bytes')
+const contentType = require('content-type')
+const typeis = require('type-is')
 
 /**
  * Module exports.
@@ -25,7 +25,7 @@ module.exports = {
  * @private
  */
 function getCharset (req) {
-  var header = req.headers['content-type']
+  const header = req.headers['content-type']
   if (!header) return undefined
   return contentType.parse(header).parameters.charset?.toLowerCase()
 }
@@ -57,13 +57,13 @@ function normalizeOptions (options, defaultType) {
     throw new TypeError('defaultType must be provided')
   }
 
-  var inflate = options?.inflate !== false
-  var limit = typeof options?.limit === 'undefined' || options?.limit === null
+  const inflate = options?.inflate !== false
+  const limit = typeof options?.limit === 'undefined' || options?.limit === null
     ? 102400 // 100kb default
     : bytes.parse(options.limit)
-  var type = options?.type || defaultType
-  var verify = options?.verify || false
-  var defaultCharset = options?.defaultCharset || 'utf-8'
+  const type = options?.type || defaultType
+  const verify = options?.verify || false
+  const defaultCharset = options?.defaultCharset || 'utf-8'
 
   if (limit === null) {
     throw new TypeError(`option limit "${String(options.limit)}" is invalid`)
@@ -74,7 +74,7 @@ function normalizeOptions (options, defaultType) {
   }
 
   // create the appropriate type checking function
-  var shouldParse = typeof type !== 'function'
+  const shouldParse = typeof type !== 'function'
     ? typeChecker(type)
     : type
 

test/body-parser.js

@@ -1,8 +1,8 @@
 'use strict'
 
-var assert = require('node:assert')
+const assert = require('node:assert')
 
-var bodyParser = require('..')
+const bodyParser = require('..')
 
 describe('bodyParser()', function () {
   it('should throw an error', function () {