diff --git a/deps/dicer/lib/Dicer.js b/deps/dicer/lib/Dicer.js
index fc50a50..483cff8 100644
--- a/deps/dicer/lib/Dicer.js
+++ b/deps/dicer/lib/Dicer.js
@@ -1,3 +1,5 @@
+'use strict'
+
 const WritableStream = require('stream').Writable
 const inherits = require('util').inherits
 
diff --git a/deps/dicer/lib/HeaderParser.js b/deps/dicer/lib/HeaderParser.js
index a11fd90..2ec8fb2 100644
--- a/deps/dicer/lib/HeaderParser.js
+++ b/deps/dicer/lib/HeaderParser.js
@@ -1,6 +1,8 @@
+'use strict'
+
 const EventEmitter = require('events').EventEmitter
 const inherits = require('util').inherits
-const getLimit = require('../../../lib/utils').getLimit
+const getLimit = require('../../../lib/utils/getLimit')
 
 const StreamSearch = require('../../streamsearch/sbmh')
 
diff --git a/deps/dicer/lib/PartStream.js b/deps/dicer/lib/PartStream.js
index c969bda..d5c0dfe 100644
--- a/deps/dicer/lib/PartStream.js
+++ b/deps/dicer/lib/PartStream.js
@@ -1,3 +1,5 @@
+'use strict'
+
 const inherits = require('util').inherits
 const ReadableStream = require('stream').Readable
 
diff --git a/deps/streamsearch/sbmh.js b/deps/streamsearch/sbmh.js
index 7f79e59..21745ac 100644
--- a/deps/streamsearch/sbmh.js
+++ b/deps/streamsearch/sbmh.js
@@ -1,3 +1,5 @@
+'use strict'
+
 /**
  * Copyright Brian White. All rights reserved.
  *
diff --git a/lib/main.js b/lib/main.js
index b0fa9f6..52206d2 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -1,10 +1,12 @@
+'use strict'
+
 const WritableStream = require('stream').Writable
 const { inherits } = require('util')
 const Dicer = require('../deps/dicer/lib/Dicer')
 
 const MultipartParser = require('./types/multipart')
 const UrlencodedParser = require('./types/urlencoded')
-const parseParams = require('./utils').parseParams
+const parseParams = require('./utils/parseParams')
 
 function Busboy (opts) {
   if (!(this instanceof Busboy)) { return new Busboy(opts) }
diff --git a/lib/types/multipart.js b/lib/types/multipart.js
index 1b3cb01..e24905c 100644
--- a/lib/types/multipart.js
+++ b/lib/types/multipart.js
@@ -1,3 +1,5 @@
+'use strict'
+
 // TODO:
 //  * support 1 nested multipart level
 //    (see second multipart example here:
@@ -10,10 +12,10 @@ const inherits = require('util').inherits
 
 const Dicer = require('../../deps/dicer/lib/Dicer')
 
-const parseParams = require('../utils').parseParams
-const decodeText = require('../utils').decodeText
-const basename = require('../utils').basename
-const getLimit = require('../utils').getLimit
+const parseParams = require('../utils/parseParams')
+const decodeText = require('../utils/decodeText')
+const basename = require('../utils/basename')
+const getLimit = require('../utils/getLimit')
 
 const RE_BOUNDARY = /^boundary$/i
 const RE_FIELD = /^form-data$/i
diff --git a/lib/types/urlencoded.js b/lib/types/urlencoded.js
index a83684e..6f5f784 100644
--- a/lib/types/urlencoded.js
+++ b/lib/types/urlencoded.js
@@ -1,6 +1,8 @@
-const Decoder = require('../utils').Decoder
-const decodeText = require('../utils').decodeText
-const getLimit = require('../utils').getLimit
+'use strict'
+
+const Decoder = require('../utils/Decoder')
+const decodeText = require('../utils/decodeText')
+const getLimit = require('../utils/getLimit')
 
 const RE_CHARSET = /^charset$/i
 
diff --git a/lib/utils.js b/lib/utils.js
deleted file mode 100644
index 1b2bd5c..0000000
--- a/lib/utils.js
+++ /dev/null
@@ -1,198 +0,0 @@
-const { TextDecoder } = require('util')
-const { TextDecoder: PolyfillTextDecoder, getEncoding } = require('text-decoding')
-
-const RE_ENCODED = /%([a-fA-F0-9]{2})/g
-const RE_PLUS = /\+/g
-
-const HEX = [
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
-  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-]
-
-// Node has always utf-8
-const textDecoders = new Map()
-textDecoders.set('utf-8', new TextDecoder('utf-8'))
-textDecoders.set('utf8', textDecoders.get('utf-8'))
-
-function encodedReplacer (match, byte) {
-  return String.fromCharCode(parseInt(byte, 16))
-}
-
-function parseParams (str) {
-  const res = []
-  let state = 'key'
-  let charset = ''
-  let inquote = false
-  let escaping = false
-  let p = 0
-  let tmp = ''
-
-  for (var i = 0, len = str.length; i < len; ++i) { // eslint-disable-line no-var
-    const char = str[i]
-    if (char === '\\' && inquote) {
-      if (escaping) { escaping = false } else {
-        escaping = true
-        continue
-      }
-    } else if (char === '"') {
-      if (!escaping) {
-        if (inquote) {
-          inquote = false
-          state = 'key'
-        } else { inquote = true }
-        continue
-      } else { escaping = false }
-    } else {
-      if (escaping && inquote) { tmp += '\\' }
-      escaping = false
-      if ((state === 'charset' || state === 'lang') && char === "'") {
-        if (state === 'charset') {
-          state = 'lang'
-          charset = tmp.substring(1)
-        } else { state = 'value' }
-        tmp = ''
-        continue
-      } else if (state === 'key' &&
-        (char === '*' || char === '=') &&
-        res.length) {
-        if (char === '*') { state = 'charset' } else { state = 'value' }
-        res[p] = [tmp, undefined]
-        tmp = ''
-        continue
-      } else if (!inquote && char === ';') {
-        state = 'key'
-        if (charset) {
-          if (tmp.length) {
-            tmp = decodeText(tmp.replace(RE_ENCODED, encodedReplacer),
-              'binary',
-              charset)
-          }
-          charset = ''
-        } else if (tmp.length) {
-          tmp = decodeText(tmp, 'binary', 'utf8')
-        }
-        if (res[p] === undefined) { res[p] = tmp } else { res[p][1] = tmp }
-        tmp = ''
-        ++p
-        continue
-      } else if (!inquote && (char === ' ' || char === '\t')) { continue }
-    }
-    tmp += char
-  }
-  if (charset && tmp.length) {
-    tmp = decodeText(tmp.replace(RE_ENCODED, encodedReplacer),
-      'binary',
-      charset)
-  } else if (tmp) {
-    tmp = decodeText(tmp, 'binary', 'utf8')
-  }
-
-  if (res[p] === undefined) {
-    if (tmp) { res[p] = tmp }
-  } else { res[p][1] = tmp }
-
-  return res
-}
-
-function decodeText (text, textEncoding, destEncoding) {
-  if (text) {
-    if (textDecoders.has(destEncoding)) {
-      try {
-        return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
-      } catch (e) { }
-    } else {
-      try {
-        textDecoders.set(destEncoding, new TextDecoder(destEncoding))
-        return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
-      } catch (e) {
-        if (getEncoding(destEncoding)) {
-          try {
-            textDecoders.set(destEncoding, new PolyfillTextDecoder(destEncoding))
-            return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
-          } catch (e) { }
-        }
-      }
-    }
-  }
-  return text
-}
-
-function Decoder () {
-  this.buffer = undefined
-}
-Decoder.prototype.write = function (str) {
-  // Replace '+' with ' ' before decoding
-  str = str.replace(RE_PLUS, ' ')
-  let res = ''
-  let i = 0; let p = 0; const len = str.length
-  for (; i < len; ++i) {
-    if (this.buffer !== undefined) {
-      if (!HEX[str.charCodeAt(i)]) {
-        res += '%' + this.buffer
-        this.buffer = undefined
-        --i // retry character
-      } else {
-        this.buffer += str[i]
-        ++p
-        if (this.buffer.length === 2) {
-          res += String.fromCharCode(parseInt(this.buffer, 16))
-          this.buffer = undefined
-        }
-      }
-    } else if (str[i] === '%') {
-      if (i > p) {
-        res += str.substring(p, i)
-        p = i
-      }
-      this.buffer = ''
-      ++p
-    }
-  }
-  if (p < len && this.buffer === undefined) { res += str.substring(p) }
-  return res
-}
-Decoder.prototype.reset = function () {
-  this.buffer = undefined
-}
-
-function basename (path) {
-  if (typeof path !== 'string') { return '' }
-  for (var i = path.length - 1; i >= 0; --i) { // eslint-disable-line no-var
-    switch (path.charCodeAt(i)) {
-      case 0x2F: // '/'
-      case 0x5C: // '\'
-        path = path.slice(i + 1)
-        return (path === '..' || path === '.' ? '' : path)
-    }
-  }
-  return (path === '..' || path === '.' ? '' : path)
-}
-
-function getLimit (limits, name, defaultLimit) {
-  if (
-    !limits ||
-    limits[name] === undefined ||
-    limits[name] === null
-  ) { return defaultLimit }
-
-  if (
-    typeof limits[name] !== 'number' ||
-    isNaN(limits[name])
-  ) { throw new TypeError('Limit ' + name + ' is not a valid number') }
-
-  return limits[name]
-}
-
-module.exports = {
-  Decoder,
-  basename,
-  getLimit,
-  parseParams,
-  decodeText
-}
diff --git a/lib/utils/Decoder.js b/lib/utils/Decoder.js
new file mode 100644
index 0000000..7917678
--- /dev/null
+++ b/lib/utils/Decoder.js
@@ -0,0 +1,54 @@
+'use strict'
+
+const RE_PLUS = /\+/g
+
+const HEX = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+]
+
+function Decoder () {
+  this.buffer = undefined
+}
+Decoder.prototype.write = function (str) {
+  // Replace '+' with ' ' before decoding
+  str = str.replace(RE_PLUS, ' ')
+  let res = ''
+  let i = 0; let p = 0; const len = str.length
+  for (; i < len; ++i) {
+    if (this.buffer !== undefined) {
+      if (!HEX[str.charCodeAt(i)]) {
+        res += '%' + this.buffer
+        this.buffer = undefined
+        --i // retry character
+      } else {
+        this.buffer += str[i]
+        ++p
+        if (this.buffer.length === 2) {
+          res += String.fromCharCode(parseInt(this.buffer, 16))
+          this.buffer = undefined
+        }
+      }
+    } else if (str[i] === '%') {
+      if (i > p) {
+        res += str.substring(p, i)
+        p = i
+      }
+      this.buffer = ''
+      ++p
+    }
+  }
+  if (p < len && this.buffer === undefined) { res += str.substring(p) }
+  return res
+}
+Decoder.prototype.reset = function () {
+  this.buffer = undefined
+}
+
+module.exports = Decoder
diff --git a/lib/utils/basename.js b/lib/utils/basename.js
new file mode 100644
index 0000000..db58819
--- /dev/null
+++ b/lib/utils/basename.js
@@ -0,0 +1,14 @@
+'use strict'
+
+module.exports = function basename (path) {
+  if (typeof path !== 'string') { return '' }
+  for (var i = path.length - 1; i >= 0; --i) { // eslint-disable-line no-var
+    switch (path.charCodeAt(i)) {
+      case 0x2F: // '/'
+      case 0x5C: // '\'
+        path = path.slice(i + 1)
+        return (path === '..' || path === '.' ? '' : path)
+    }
+  }
+  return (path === '..' || path === '.' ? '' : path)
+}
diff --git a/lib/utils/decodeText.js b/lib/utils/decodeText.js
new file mode 100644
index 0000000..ec47716
--- /dev/null
+++ b/lib/utils/decodeText.js
@@ -0,0 +1,60 @@
+'use strict'
+
+let TextDecoder
+try {
+  TextDecoder = require('util').TextDecoder
+} catch (e) { }
+
+const { TextDecoder: PolyfillTextDecoder, getEncoding } = require('text-decoding')
+
+// Node has always utf-8
+const textDecoders = new Map()
+if (TextDecoder) {
+  textDecoders.set('utf-8', new TextDecoder('utf-8'))
+} else {
+  textDecoders.set('utf-8', new PolyfillTextDecoder('utf-8'))
+}
+textDecoders.set('utf8', textDecoders.get('utf-8'))
+
+function decodeText (text, textEncoding, destEncoding) {
+  if (text) {
+    if (textDecoders.has(destEncoding)) {
+      try {
+        return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
+      } catch (e) { }
+    } else {
+      try {
+        textDecoders.set(destEncoding, new TextDecoder(destEncoding))
+        return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
+      } catch (e) {
+        if (getEncoding(destEncoding)) {
+          try {
+            textDecoders.set(destEncoding, new PolyfillTextDecoder(destEncoding))
+            return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
+          } catch (e) { }
+        }
+      }
+    }
+  }
+  return text
+}
+
+function decodeTextPolyfill (text, textEncoding, destEncoding) {
+  if (text) {
+    if (textDecoders.has(destEncoding)) {
+      try {
+        return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
+      } catch (e) { }
+    } else {
+      if (getEncoding(destEncoding)) {
+        try {
+          textDecoders.set(destEncoding, new PolyfillTextDecoder(destEncoding))
+          return textDecoders.get(destEncoding).decode(Buffer.from(text, textEncoding))
+        } catch (e) { }
+      }
+    }
+  }
+  return text
+}
+
+module.exports = TextDecoder ? decodeText : decodeTextPolyfill
diff --git a/lib/utils/getLimit.js b/lib/utils/getLimit.js
new file mode 100644
index 0000000..cb64fd6
--- /dev/null
+++ b/lib/utils/getLimit.js
@@ -0,0 +1,16 @@
+'use strict'
+
+module.exports = function getLimit (limits, name, defaultLimit) {
+  if (
+    !limits ||
+    limits[name] === undefined ||
+    limits[name] === null
+  ) { return defaultLimit }
+
+  if (
+    typeof limits[name] !== 'number' ||
+    isNaN(limits[name])
+  ) { throw new TypeError('Limit ' + name + ' is not a valid number') }
+
+  return limits[name]
+}
diff --git a/lib/utils/parseParams.js b/lib/utils/parseParams.js
new file mode 100644
index 0000000..f921418
--- /dev/null
+++ b/lib/utils/parseParams.js
@@ -0,0 +1,87 @@
+'use strict'
+
+const decodeText = require('./decodeText')
+
+const RE_ENCODED = /%([a-fA-F0-9]{2})/g
+
+function encodedReplacer (match, byte) {
+  return String.fromCharCode(parseInt(byte, 16))
+}
+
+function parseParams (str) {
+  const res = []
+  let state = 'key'
+  let charset = ''
+  let inquote = false
+  let escaping = false
+  let p = 0
+  let tmp = ''
+
+  for (var i = 0, len = str.length; i < len; ++i) { // eslint-disable-line no-var
+    const char = str[i]
+    if (char === '\\' && inquote) {
+      if (escaping) { escaping = false } else {
+        escaping = true
+        continue
+      }
+    } else if (char === '"') {
+      if (!escaping) {
+        if (inquote) {
+          inquote = false
+          state = 'key'
+        } else { inquote = true }
+        continue
+      } else { escaping = false }
+    } else {
+      if (escaping && inquote) { tmp += '\\' }
+      escaping = false
+      if ((state === 'charset' || state === 'lang') && char === "'") {
+        if (state === 'charset') {
+          state = 'lang'
+          charset = tmp.substring(1)
+        } else { state = 'value' }
+        tmp = ''
+        continue
+      } else if (state === 'key' &&
+        (char === '*' || char === '=') &&
+        res.length) {
+        if (char === '*') { state = 'charset' } else { state = 'value' }
+        res[p] = [tmp, undefined]
+        tmp = ''
+        continue
+      } else if (!inquote && char === ';') {
+        state = 'key'
+        if (charset) {
+          if (tmp.length) {
+            tmp = decodeText(tmp.replace(RE_ENCODED, encodedReplacer),
+              'binary',
+              charset)
+          }
+          charset = ''
+        } else if (tmp.length) {
+          tmp = decodeText(tmp, 'binary', 'utf8')
+        }
+        if (res[p] === undefined) { res[p] = tmp } else { res[p][1] = tmp }
+        tmp = ''
+        ++p
+        continue
+      } else if (!inquote && (char === ' ' || char === '\t')) { continue }
+    }
+    tmp += char
+  }
+  if (charset && tmp.length) {
+    tmp = decodeText(tmp.replace(RE_ENCODED, encodedReplacer),
+      'binary',
+      charset)
+  } else if (tmp) {
+    tmp = decodeText(tmp, 'binary', 'utf8')
+  }
+
+  if (res[p] === undefined) {
+    if (tmp) { res[p] = tmp }
+  } else { res[p][1] = tmp }
+
+  return res
+}
+
+module.exports = parseParams
diff --git a/test/decoder.spec.js b/test/decoder.spec.js
index 3a70756..99c551a 100644
--- a/test/decoder.spec.js
+++ b/test/decoder.spec.js
@@ -1,5 +1,5 @@
 const { assert, expect } = require('chai')
-const { Decoder } = require('../lib/utils')
+const Decoder = require('../lib/utils/Decoder')
 
 describe('Decoder', () => {
   [
diff --git a/test/get-limit.spec.js b/test/get-limit.spec.js
index 39e7cb6..7586f73 100644
--- a/test/get-limit.spec.js
+++ b/test/get-limit.spec.js
@@ -1,4 +1,4 @@
-const { getLimit } = require('../lib/utils')
+const getLimit = require('../lib/utils/getLimit')
 const { assert } = require('chai')
 
 describe('Get limit', () => {
diff --git a/test/parse-params.spec.js b/test/parse-params.spec.js
index a4a9e4f..1032d14 100644
--- a/test/parse-params.spec.js
+++ b/test/parse-params.spec.js
@@ -1,6 +1,6 @@
 const { inspect } = require('util')
 const { assert } = require('chai')
-const { parseParams } = require('../lib/utils')
+const parseParams = require('../lib/utils/parseParams')
 
 describe('parse-params', () => {
   [