1diff --git a/ts/Errors.ts b/ts/Errors.ts
 2new file mode 100644
 3index 0000000..0e6d73a
 4--- /dev/null
 5+++ b/ts/Errors.ts
 6@@ -0,0 +1,23 @@
 7+var Errors = {
 8+  errors: [
 9+    {type: 'NULL', output: '#NULL'},
10+    {type: 'DIV_ZERO', output: '#DIV/0!'},
11+    {type: 'VALUE', output: '#VALUE!'},
12+    {type: 'REF', output: '#REF!'},
13+    {type: 'NAME', output: '#NAME?'},
14+    {type: 'NUM', output: '#NUM!'},
15+    {type: 'NOT_AVAILABLE', output: '#N/A!'},
16+    {type: 'ERROR', output: '#ERROR'}
17+  ],
18+  get: function (type) {
19+    var error = Errors.errors.filter(function (item) {
20+      return item.type === type || item.output === type;
21+    })[0];
22+
23+    return error ? error.output : null;
24+  }
25+};
26+
27+export {
28+  Errors
29+}
30\ No newline at end of file
31diff --git a/ts/Sheet.ts b/ts/Sheet.ts
32index 1559b35..e0622fc 100644
33--- a/ts/Sheet.ts
34+++ b/ts/Sheet.ts
35@@ -2,6 +2,7 @@
36 import { Parser } from "./Parser";
37 import { A1CellKey } from "./A1CellKey"
38 import { Cell } from "./Cell"
39+import { Errors } from "./Errors"
40 import * as Formula from "formulajs"
41 
42 var Sheet = (function () {
43@@ -42,27 +43,6 @@ var Sheet = (function () {
44     return newParser;
45   };
46 
47-  var Exception = {
48-    errors: [
49-      {type: 'NULL', output: '#NULL'},
50-      {type: 'DIV_ZERO', output: '#DIV/0!'},
51-      {type: 'VALUE', output: '#VALUE!'},
52-      {type: 'REF', output: '#REF!'},
53-      {type: 'NAME', output: '#NAME?'},
54-      {type: 'NUM', output: '#NUM!'},
55-      {type: 'NOT_AVAILABLE', output: '#N/A!'},
56-      {type: 'ERROR', output: '#ERROR'}
57-    ],
58-    get: function (type) {
59-      var error = Exception.errors.filter(function (item) {
60-        return item.type === type || item.output === type;
61-      })[0];
62-
63-      return error ? error.output : null;
64-    }
65-  };
66-
67-
68   class Matrix {
69     public data: Array<Cell>;
70     constructor() {
71@@ -568,17 +548,17 @@ var Sheet = (function () {
72         result = null;
73         deps.forEach(function (id) {
74           // instance.matrix.updateItem(id, {value: null, error: Exception.get('REF')});
75-          instance.matrix.getItem(new A1CellKey(id)).setError(Exception.get('REF'));
76+          instance.matrix.getItem(new A1CellKey(id)).setError(Errors.get('REF'));
77           instance.matrix.getItem(new A1CellKey(id)).setValue(null);
78         });
79         throw Error('REF');
80       }
81     } catch (ex) {
82-      var message = Exception.get(ex.message);
83+      var message = Errors.get(ex.message);
84       if (message) {
85         error = message;
86       } else {
87-        error = Exception.get('ERROR');
88+        error = Errors.get('ERROR');
89       }
90     }
91