diff --git a/dist/setup.js b/dist/setup.js
index d2b3d89..50326f5 100644
--- a/dist/setup.js
+++ b/dist/setup.js
@@ -1,59 +1,51 @@
 'use strict';
 
 class LocalStorage {
-    constructor() {
-        Object.defineProperty(this, "getItem", {
-            enumerable: false,
-            value: jest.fn(key => {
-                return this[key] || null;
-            })
-
-        });
-        Object.defineProperty(this, "setItem", {
-            enumerable: false,
-            value: jest.fn((key, val = '') => {
-                this[key] = val + '';
-            })
-        });
-        Object.defineProperty(this, "removeItem", {
-            enumerable: false,
-            value: jest.fn(key => {
-                delete this[key];
-            })
-        });
-        Object.defineProperty(this, "clear", {
-            enumerable: false,
-            value: jest.fn(() => {
-                Object.keys(this).map(key => delete this[key]);
-            })
-        });
-        Object.defineProperty(this, "toString", {
-            enumerable: false,
-            value: jest.fn(() => {
-                return "[object Storage]";
-            })
-        });
-        Object.defineProperty(this, "key", {
-            enumerable: false,
-            value: jest.fn(idx => {
-                return Object.keys(this)[idx] || null;
-            })
-        });
-    } // end constructor
-
-    get length() {
-        return Object.keys(this).length;
-    }
-
-    get __STORE__() {
-        return this;
-    }
+  constructor(jest) {
+    Object.defineProperty(this, 'getItem', {
+      enumerable: false,
+      value: jest.fn(key => this[key] || null)
+    });
+    Object.defineProperty(this, 'setItem', {
+      enumerable: false,
+      // not mentioned in the spec, but we must always coerce to a string
+      value: jest.fn((key, val = '') => {
+        this[key] = val + '';
+      })
+    });
+    Object.defineProperty(this, 'removeItem', {
+      enumerable: false,
+      value: jest.fn(key => {
+        delete this[key];
+      })
+    });
+    Object.defineProperty(this, 'clear', {
+      enumerable: false,
+      value: jest.fn(() => {
+        Object.keys(this).map(key => delete this[key]);
+      })
+    });
+    Object.defineProperty(this, 'toString', {
+      enumerable: false,
+      value: jest.fn(() => {
+        return '[object Storage]';
+      })
+    });
+    Object.defineProperty(this, 'key', {
+      enumerable: false,
+      value: jest.fn(idx => Object.keys(this)[idx] || null)
+    });
+  } // end constructor
 
+  get length() {
+    return Object.keys(this).length;
+  }
+  // for backwards compatibility
+  get __STORE__() {
+    return this;
+  }
 }
 
-const local = new LocalStorage();
-const session = new LocalStorage();
-
-global.localStorage = local;
-global.sessionStorage = session;
+global.localStorage = new LocalStorage(jest);
+global.sessionStorage = new LocalStorage(jest);
 //# sourceMappingURL=setup.js.map
diff --git a/dist/setup.js.map b/dist/setup.js.map
index 7cc37c2..81f7469 100644
--- a/dist/setup.js.map
+++ b/dist/setup.js.map
@@ -1 +1 @@
-{"version":3,"file":"setup.js","sources":["../src/localstorage.js","../src/setup.js"],"sourcesContent":["export class LocalStorage  {\n    constructor() {\n        Object.defineProperty(this, \"getItem\", {\n            enumerable: false,\n            value: jest.fn((key) => {return this[key] || null })\n\n        });\n        Object.defineProperty(this, \"setItem\", {\n            enumerable: false,\n            value: jest.fn((key, val = '') => {\n                this[key] = val + '';\n            })\n        });\n        Object.defineProperty(this, \"removeItem\", {\n            enumerable: false,\n            value: jest.fn((key) => {\n                delete this[key];\n            })\n        });\n        Object.defineProperty(this, \"clear\", {\n            enumerable: false,\n            value: jest.fn(() => {\n                Object.keys(this).map(key => delete this[key]);\n\n            })\n        });\n        Object.defineProperty(this, \"toString\", {\n            enumerable: false,\n            value: jest.fn(() => {\n                return \"[object Storage]\"\n\n            })\n        });\n        Object.defineProperty(this, \"key\", {\n            enumerable: false,\n            value: jest.fn((idx) => {\n                return Object.keys(this)[idx] || null\n            })\n        });\n\n    } // end constructor\n\n    get length() {\n        return Object.keys(this).length\n    }\n\n    get __STORE__() {\n        return this\n    }\n\n}\n\n","import { LocalStorage } from './localstorage';\n\nconst local = new LocalStorage();\nconst session = new LocalStorage();\n\nglobal.localStorage = local;\nglobal.sessionStorage = session;\n\n\n"],"names":["LocalStorage","defineProperty","jest","fn","key","val","keys","map","idx","Object","length","__STORE__","local","session","global","localStorage","sessionStorage"],"mappings":";;AAAO,MAAMA,YAAN,CAAoB;kBACT;eACHC,cAAP,CAAsB,IAAtB,EAA4B,SAA5B,EAAuC;wBACvB,KADuB;mBAE5BC,KAAKC,EAAL,CAASC,GAAD,IAAS;uBAAQ,KAAKA,GAAL,KAAa,IAApB;aAAlB;;SAFX;eAKOH,cAAP,CAAsB,IAAtB,EAA4B,SAA5B,EAAuC;wBACvB,KADuB;mBAE5BC,KAAKC,EAAL,CAAQ,CAACC,GAAD,EAAMC,MAAM,EAAZ,KAAmB;qBACzBD,GAAL,IAAYC,MAAM,EAAlB;aADG;SAFX;eAMOJ,cAAP,CAAsB,IAAtB,EAA4B,YAA5B,EAA0C;wBAC1B,KAD0B;mBAE/BC,KAAKC,EAAL,CAASC,GAAD,IAAS;uBACb,KAAKA,GAAL,CAAP;aADG;SAFX;eAMOH,cAAP,CAAsB,IAAtB,EAA4B,OAA5B,EAAqC;wBACrB,KADqB;mBAE1BC,KAAKC,EAAL,CAAQ,MAAM;uBACVG,IAAP,CAAY,IAAZ,EAAkBC,GAAlB,CAAsBH,OAAO,OAAO,KAAKA,GAAL,CAApC;aADG;SAFX;eAOOH,cAAP,CAAsB,IAAtB,EAA4B,UAA5B,EAAwC;wBACxB,KADwB;mBAE7BC,KAAKC,EAAL,CAAQ,MAAM;uBACV,kBAAP;aADG;SAFX;eAOOF,cAAP,CAAsB,IAAtB,EAA4B,KAA5B,EAAmC;wBACnB,KADmB;mBAExBC,KAAKC,EAAL,CAASK,GAAD,IAAS;uBACbC,OAAOH,IAAP,CAAY,IAAZ,EAAkBE,GAAlB,KAA0B,IAAjC;aADG;SAFX;KAjCmB;;QA0CnBE,MAAJ,GAAa;eACFD,OAAOH,IAAP,CAAY,IAAZ,EAAkBI,MAAzB;;;QAGAC,SAAJ,GAAgB;eACL,IAAP;;;;;AC7CR,MAAMC,QAAQ,IAAIZ,YAAJ,EAAd;AACA,MAAMa,UAAU,IAAIb,YAAJ,EAAhB;;AAEAc,OAAOC,YAAP,GAAsBH,KAAtB;AACAE,OAAOE,cAAP,GAAwBH,OAAxB"}
\ No newline at end of file
+{"version":3,"file":"setup.js","sources":["../src/localstorage.js","../src/setup.js"],"sourcesContent":["export class LocalStorage {\n  constructor(jest) {\n    Object.defineProperty(this, 'getItem', {\n      enumerable: false,\n      value: jest.fn(key => this[key] || null),\n    });\n    Object.defineProperty(this, 'setItem', {\n      enumerable: false,\n      // not mentioned in the spec, but we must always coerce to a string\n      value: jest.fn((key, val = '') => {\n        this[key] = val + '';\n      }),\n    });\n    Object.defineProperty(this, 'removeItem', {\n      enumerable: false,\n      value: jest.fn(key => {\n        delete this[key];\n      }),\n    });\n    Object.defineProperty(this, 'clear', {\n      enumerable: false,\n      value: jest.fn(() => {\n        Object.keys(this).map(key => delete this[key]);\n      }),\n    });\n    Object.defineProperty(this, 'toString', {\n      enumerable: false,\n      value: jest.fn(() => {\n        return '[object Storage]';\n      }),\n    });\n    Object.defineProperty(this, 'key', {\n      enumerable: false,\n      value: jest.fn(idx => Object.keys(this)[idx] || null),\n    });\n  } // end constructor\n\n  get length() {\n    return Object.keys(this).length;\n  }\n  // for backwards compatibility\n  get __STORE__() {\n    return this;\n  }\n}\n","import { LocalStorage } from './localstorage';\n\nglobal.localStorage = new LocalStorage(jest);\nglobal.sessionStorage = new LocalStorage(jest);\n"],"names":["LocalStorage","jest","defineProperty","fn","key","val","keys","map","idx","Object","length","__STORE__","global","localStorage","sessionStorage"],"mappings":";;AAAO,MAAMA,YAAN,CAAmB;cACZC,IAAZ,EAAkB;WACTC,cAAP,CAAsB,IAAtB,EAA4B,SAA5B,EAAuC;kBACzB,KADyB;aAE9BD,KAAKE,EAAL,CAAQC,OAAO,KAAKA,GAAL,KAAa,IAA5B;KAFT;WAIOF,cAAP,CAAsB,IAAtB,EAA4B,SAA5B,EAAuC;kBACzB,KADyB;;aAG9BD,KAAKE,EAAL,CAAQ,CAACC,GAAD,EAAMC,MAAM,EAAZ,KAAmB;aAC3BD,GAAL,IAAYC,MAAM,EAAlB;OADK;KAHT;WAOOH,cAAP,CAAsB,IAAtB,EAA4B,YAA5B,EAA0C;kBAC5B,KAD4B;aAEjCD,KAAKE,EAAL,CAAQC,OAAO;eACb,KAAKA,GAAL,CAAP;OADK;KAFT;WAMOF,cAAP,CAAsB,IAAtB,EAA4B,OAA5B,EAAqC;kBACvB,KADuB;aAE5BD,KAAKE,EAAL,CAAQ,MAAM;eACZG,IAAP,CAAY,IAAZ,EAAkBC,GAAlB,CAAsBH,OAAO,OAAO,KAAKA,GAAL,CAApC;OADK;KAFT;WAMOF,cAAP,CAAsB,IAAtB,EAA4B,UAA5B,EAAwC;kBAC1B,KAD0B;aAE/BD,KAAKE,EAAL,CAAQ,MAAM;eACZ,kBAAP;OADK;KAFT;WAMOD,cAAP,CAAsB,IAAtB,EAA4B,KAA5B,EAAmC;kBACrB,KADqB;aAE1BD,KAAKE,EAAL,CAAQK,OAAOC,OAAOH,IAAP,CAAY,IAAZ,EAAkBE,GAAlB,KAA0B,IAAzC;KAFT;GA/BsB;;MAqCpBE,MAAJ,GAAa;WACJD,OAAOH,IAAP,CAAY,IAAZ,EAAkBI,MAAzB;;;MAGEC,SAAJ,GAAgB;WACP,IAAP;;;;ACxCJC,OAAOC,YAAP,GAAsB,IAAIb,YAAJ,CAAiBC,IAAjB,CAAtB;AACAW,OAAOE,cAAP,GAAwB,IAAId,YAAJ,CAAiBC,IAAjB,CAAxB"}
\ No newline at end of file