feat(util): isolate lodash instance on collection

util manages an isolated instance of lodash to wrap collections and exposes a method to add mixins
to the same instance.

lib/util.js

@@ -13,6 +13,7 @@ const i = require('inflect')
 const _ = require('lodash')
 const humanize = require('humanize-number')
 const util = exports = module.exports = {}
+const isolatedLodash = _.runInContext()
 
 /**
  * makes table name from a class defination
@@ -84,7 +85,35 @@ util.pick = function (values, valuesToOmit) {
  * @public
  */
 util.toCollection = function (values) {
-  return _(values)
+  return isolatedLodash(values)
+}
+
+/**
+ * returns isolated instance of lodash, it is also
+ * used while wrapping values in a collection.
+ *
+ * @method lodash
+ *
+ * @return {Object}
+ */
+util.lodash = function () {
+  return isolatedLodash
+}
+
+/**
+ * adds a mixin to the lodash instance
+ *
+ * @method addMixin
+ * @param  {String} name
+ * @param  {Function} method
+ * @param  {Object} extra
+ *
+ * @public
+ */
+util.addMixin = function (name, method) {
+  const mixin = {}
+  mixin[name] = method
+  isolatedLodash.mixin(mixin)
 }
 
 /**

test/unit/util.spec.js

@@ -11,6 +11,7 @@
 
 /* global describe, it*/
 const util = require('../../lib/util')
+const _ = require('lodash')
 const chai = require('chai')
 const expect = chai.expect
 
@@ -112,4 +113,11 @@ describe('Utils', function () {
     const meta = util.makePaginateMeta(20, 1, 10)
     expect(meta).deep.equal({total: 20, perPage: 10, currentPage: 1, lastPage: 2, data: []})
   })
+
+  it('should add a mixin to lodash isolated instance', function () {
+    const foo = function () {}
+    util.addMixin('foo', foo)
+    expect(_.isFunction(_.foo)).to.equal(false)
+    expect(_.isFunction(util.lodash().foo)).to.equal(true)
+  })
 })