perf: lazily instantiate faker (#153)

lib/helpers.js

@@ -25,10 +25,8 @@
 'use strict';
 
 var _ = require('lodash');
-var fakerLocale = require('faker/locale/en_US');
 var formatGenerators = require('./validation/format-generators');
 var formatValidators = require('./validation/format-validators');
-var mocker = require('json-schema-faker/lib');
 var ZSchema = require('z-schema');
 
 // full-date from http://xml2rfc.ietf.org/public/rfc/html/rfc3339.html#anchor14
@@ -60,7 +58,7 @@ var dateTimeRegExp = new RegExp(
   '$');
 
 var collectionFormats = [undefined, 'csv', 'multi', 'pipes', 'ssv', 'tsv'];
-var jsonMocker = createJSONMocker();
+var jsonMocker;
 var jsonSchemaValidator = createJSONValidator();
 // https://github.com/swagger-api/swagger-spec/blob/master/versions/2.0.md#parameter-object
 var parameterSchemaProperties = [
@@ -85,8 +83,10 @@ var parameterSchemaProperties = [
 ];
 var types = ['array', 'boolean', 'integer', 'object', 'number', 'string'];
 
-function createJSONMocker () {
+function createJSONMocker (mocker) {
   // Extend faker.js to only include the 'en' locale
+  var fakerLocale = require('faker/locale/en_US');
+
   mocker.extend('faker', function () {
     return fakerLocale;
   });
@@ -376,9 +376,14 @@ var getHeaderValue = module.exports.getHeaderValue = function (headers, headerNa
  * @returns {object} The json-schema-faker mocker to use
  */
 module.exports.getJSONSchemaMocker = function () {
+  var mocker;
+
+  if (!jsonMocker) {
+    mocker = require('json-schema-faker/lib');
+    jsonMocker = createJSONMocker(mocker);
+  }
   return jsonMocker;
 };
-
 /**
  * Returns a z-schema validator.
  *