move checkParameters to separate file

Author: fanatid

browser.js

@@ -1,31 +1,13 @@
 var createHmac = require('create-hmac')
-
-var MAX_ALLOC = Math.pow(2, 30) - 1 // default in iojs
-exports._checkParameters = function (iterations, keylen) {
-  if (typeof iterations !== 'number') {
-    throw new TypeError('Iterations not a number')
-  }
-
-  if (iterations < 0) {
-    throw new TypeError('Bad iterations')
-  }
-
-  if (typeof keylen !== 'number') {
-    throw new TypeError('Key length not a number')
-  }
-
-  if (keylen < 0 || keylen > MAX_ALLOC || keylen !== keylen) { /* eslint no-self-compare: 0 */
-    throw new TypeError('Bad key length')
-  }
-}
+var checkParameters = require('./precondition')
 
 exports.pbkdf2 = function (password, salt, iterations, keylen, digest, callback) {
   if (typeof digest === 'function') {
     callback = digest
     digest = undefined
   }
 
-  exports._checkParameters(iterations, keylen)
+  checkParameters(iterations, keylen)
   if (typeof callback !== 'function') throw new Error('No callback provided to pbkdf2')
 
   setTimeout(function () {
@@ -37,7 +19,7 @@ exports.pbkdf2Sync = function (password, salt, iterations, keylen, digest) {
   if (!Buffer.isBuffer(password)) password = new Buffer(password, 'binary')
   if (!Buffer.isBuffer(salt)) salt = new Buffer(salt, 'binary')
 
-  exports._checkParameters(iterations, keylen)
+  checkParameters(iterations, keylen)
 
   digest = digest || 'sha1'
 

node-shim.js

@@ -2,6 +2,7 @@ var crypto = require('crypto')
 var fork = require('child_process').fork
 var path = require('path')
 var browser = require('./browser')
+var checkParameters = require('./precondition')
 
 var isShimRequired = null
 exports.isShimRequired = function () {
@@ -30,7 +31,7 @@ exports.pbkdf2 = function pbkdf2 (password, salt, iterations, keylen, digest, ca
   if (!Buffer.isBuffer(password)) password = new Buffer(password, 'binary')
   if (!Buffer.isBuffer(salt)) salt = new Buffer(salt, 'binary')
 
-  browser._checkParameters(iterations, keylen)
+  checkParameters(iterations, keylen)
   var child = fork(path.resolve(__dirname, 'async-shim.js'))
 
   child.on('message', function (result) {

package.json

@@ -7,7 +7,8 @@
     "async-shim.js",
     "browser.js",
     "index.js",
-    "node-shim.js"
+    "node-shim.js",
+    "precondition.js"
   ],
   "browser": "./browser.js",
   "keywords": [

precondition.js

@@ -0,0 +1,18 @@
+var MAX_ALLOC = Math.pow(2, 30) - 1 // default in iojs
+module.exports = function (iterations, keylen) {
+  if (typeof iterations !== 'number') {
+    throw new TypeError('Iterations not a number')
+  }
+
+  if (iterations < 0) {
+    throw new TypeError('Bad iterations')
+  }
+
+  if (typeof keylen !== 'number') {
+    throw new TypeError('Key length not a number')
+  }
+
+  if (keylen < 0 || keylen > MAX_ALLOC || keylen !== keylen) { /* eslint no-self-compare: 0 */
+    throw new TypeError('Bad key length')
+  }
+}