bug(datatypes) Lazy-load pg-hstore to prevent error about missing pg-hstore in o…

…ther dialects. Thanks to breakingthings

lib/data-types.js

@@ -7,8 +7,7 @@ var util = require('util')
   , sequelizeErrors = require('./errors')
   , warnings = {}
   , Validator = require('validator')
-  , moment = require('moment-timezone')
-  , hstore = require('./dialects/postgres/hstore');
+  , moment = require('moment-timezone');
 
 /**
  * A convenience class holding commonly used data types. The datatypes are used when defining a new model using `Sequelize.define`, like this:
@@ -478,11 +477,6 @@ HSTORE.prototype.validate = function(value) {
   return true;
 };
 
-HSTORE.prototype.escape = false;
-HSTORE.prototype.$stringify = function (value) {
-  return '\'' + hstore.stringify(value) + '\'';
-};
-
 /**
  * A JSON string column. Only available in postgres.
  * @property JSON

lib/dialects/postgres/data-types.js

@@ -3,8 +3,7 @@
 /*jshint -W110 */
 
 var _ = require('lodash')
-  , wkx = require('wkx')
-  , hstore = require('./hstore');
+  , wkx = require('wkx');
 
 module.exports = function (BaseTypes) {
   var warn = BaseTypes.ABSTRACT.warn.bind(undefined, 'http://www.postgresql.org/docs/9.4/static/datatype.html');
@@ -270,12 +269,26 @@ module.exports = function (BaseTypes) {
     return 'ST_GeomFromGeoJSON(\'' + JSON.stringify(value) + '\')';
   };
 
-  var HSTORE = BaseTypes.HSTORE.inherits();
+  var hstore;
+  var HSTORE = BaseTypes.HSTORE.inherits(function () {
+    if (!(this instanceof HSTORE)) return new HSTORE();
+    BaseTypes.HSTORE.apply(this, arguments);
+
+    if (!hstore) {
+      // All datatype files are loaded at import - make sure we don't load the hstore parser before a hstore is instantiated
+      hstore = require('./hstore');
+    }
+  });
 
   HSTORE.parse = function (value) {
     return hstore.parse(value);
   };
 
+  HSTORE.prototype.escape = false;
+  HSTORE.prototype.$stringify = function (value) {
+    return "'" + hstore.stringify(value) + "'";
+  };
+
   BaseTypes.HSTORE.types.postgres = {
     oids: [],
     array_oids: []