diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 0000000..2622a5c
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,54 @@
+workflows:
+  version: 2
+  node-multi-build:
+    jobs:
+      - node-v8
+      - node-v10
+      - node-v12
+      - node-v14
+version: 2
+jobs:
+  node-base: &node-base
+    docker:
+      - image: node
+    steps:
+      - checkout
+      - restore_cache:
+          keys:
+            - npm-lock-{{ .Branch }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package.json" }}
+            - npm-lock-master-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package.json" }}
+            - npm-cache-{{ .Branch }}-{{ .Environment.CIRCLE_JOB }}
+            - npm-cache-master-{{ .Environment.CIRCLE_JOB }}
+      - run:
+          name: Install dependencies
+          command: npm install
+      - run:
+          name: Build
+          command: npm run build
+      - run:
+          name: Test
+          command: npm run test
+      - save_cache:
+          key: npm-lock-{{ .Branch }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package.json" }}
+          paths:
+            - node_modules
+      - save_cache:
+          key: npm-cache-{{ .Branch }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package.json" }}
+          paths:
+            - ~/.npm/_cacache
+  node-v8:
+    <<: *node-base
+    docker:
+      - image: circleci/node:8
+  node-v10:
+    <<: *node-base
+    docker:
+      - image: circleci/node:10
+  node-v12:
+    <<: *node-base
+    docker:
+      - image: circleci/node:12
+  node-v14:
+    <<: *node-base
+    docker:
+      - image: circleci/node:14
diff --git a/.gitignore b/.gitignore
index 9aeb862..9c6fc03 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,12 @@
+# intellij idea
+.idea
+
+
 # Logs
 logs
 *.log
 npm-debug.log*
+package-lock.json
 
 # Runtime data
 pids
@@ -38,3 +43,6 @@ jspm_packages
 
 # Yarn
 yarn.lock
+
+# Direnv
+.envrc
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bfcdc58..636b0cc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,17 +1,65 @@
 
+1.9.0 / 2018-04-17
+==================
+
+  * Feature: Added `internalData` property for non-serialized context data (@n1ru4l, #41)
+
+1.8.0 / 2018-04-10
+==================
+
+  * Fix: Wrong and missing data being returned in errors (@thebigredgeek)
+  * Fix: Reverted breaking change regarding spec compliance (@thebigredgeek)
+
+1.7.1 / 2018-02-22
+==================
+
+  * Fix: less ambiguity around data type (@thebigredgeek)
+
+1.7.0 / 2018-02-22
+==================
+
+  * Misc: Refactored in TypeScript (#19, #22, @iamdanthdev, @lakhansamani)
+  * Fix: Fix createError interface post-typescript refactor (@thebigredgeek)
+  * Fix: Fix showPath option to correctly toggle error path exposure regardless of showLocation state (@thebigredgeek)
+
+1.5.1 / 2017-09-07
+==================
+
+  * Package: Added new keywords (@thebigredgeek)
+  * Docs: Updated docs to reference [apollo-server](https://dev.apollodata.com/tools/apollo-server/setup.html) (@thebigredgeek) 
+
+1.5.0 / 2017-08-29
+==================
+
+  * Fix: fixed syntax error for createError config parameter (@thebigredgeek)
+
+1.4.0 / 2017-03-14
+==================
+  * Feature: (BREAKING) Rely on error.originalError and fail back to error for formatError rather than serializing body into message
+  * Docs: Add docs for `isInstance`
+
+1.3.0 / 2017-02-01
+==================
+  * Docs: Update README.md (@thebigredgeek)
+  * Docs: Add Beerpay's badge (@thebigredgeek)
+  * Docs: Added isInstance method
+
+1.2.1 / 2016-12-07
+==================
+  * Fix: bug with overriding message serialization (@thebigredgeek)
+
 1.2.0 / 2016-12-07
 ==================
-  * Added option to override message when throwing error (@thebigredgeek)
+  * Feature: Added option to override message when throwing error (@thebigredgeek)
 
 1.1.0 / 2016-12-01
 ==================
-  * Added option to show original locations and paths in error (#1, @scf4)
+  * Feature: Added option to show original locations and paths in error (#1, @scf4)
 
 1.0.2 / 2016-11-11
 ==================
-  * Fix for data serialization (@thebigredgeek)
+  * Fix: data serialization (@thebigredgeek)
 
 1.0.1 / 2016-11-10
 ==================
-
   * Initial release (@thebigredgeek)
diff --git a/Makefile b/Makefile
index bf4762d..8b3638a 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ endif
 .FORCE:
 
 all: clean
-	babel src -d dist --source-maps
+	tsc
 
 clean: .FORCE
 	rimraf npm-debug.log dist
diff --git a/README.md b/README.md
index 7ef6ac1..2446d07 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,9 @@ Machine-readable custom errors for Apollostack's GraphQL server
 
 [![CircleCI](https://circleci.com/gh/thebigredgeek/apollo-errors.svg?style=shield)](https://circleci.com/gh/thebigredgeek/apollo-errors/tree/master)
 
+## Example from Apollo Day
+
+[![Authentication and Error Handling in GraphQL](https://img.youtube.com/vi/xaorvBjCE7A/0.jpg)](https://www.youtube.com/watch?v=xaorvBjCE7A)
 
 ## Installation and usage
 
@@ -30,6 +33,7 @@ Hook up formatting:
 import express from 'express';
 import bodyParser from 'body-parser';
 import { formatError } from 'apollo-errors';
+import { graphqlExpress } from 'apollo-server-express';
 import schema from './schema';
 
 const app = express();
@@ -54,6 +58,9 @@ const resolverThatThrowsError = (root, params, context) => {
   throw new FooError({
     data: {
       something: 'important'
+    },
+    internalData: {
+      error: `The SQL server died.`
     }
   });
 }
@@ -79,18 +86,39 @@ Witness glorious simplicity:
 }
 ```
 
+The `internalData` property is meant for data you want to store on the error object (e.g. for logging), but not send out to your end users.
+You can utilize this data for logging purposes.
+
+```js
+import { isInstance as isApolloErrorInstance, formatError as formatApolloError } from 'apollo-errors';
+
+function formatError(error) {
+  const { originalError } = error;
+  if (isApolloErrorInstance(originalError)) {
+    // log internalData to stdout but not include it in the formattedError
+    console.log(JSON.stringify({
+      type: `error`,
+      data: originalError.data,
+      internalData: originalError.internalData
+    }));
+  }
+  return formatApolloError(error)
+}
+
+``` 
+
 ## API
 
-### ApolloError ({ [time_thrown: String, data: Object, message: String ]})
+### ApolloError ({ [time_thrown: String, data: Object, internalData: object, message: String ]})
 
 Creates a new ApolloError object.  Note that `ApolloError` in this context refers
 to an error class created and returned by `createError` documented below.  Error can be
-initialized with a custom `time_thrown` ISODate (default is current ISODate), `data` object (which will be merged with data specified through `createError`, if it exists), and `message` (which will override the message specified through `createError`).
+initialized with a custom `time_thrown` ISODate (default is current ISODate), `data` object (which will be merged with data specified through `createError`, if it exists), `internalData` object (which will be merged with internalData specified trough `createError`) and `message` (which will override the message specified through `createError`).
 
 
-### createError(name, {message: String, [data: Object, options: Object]}): ApolloError
+### createError(name, {message: String, [data: Object, internalData: object, options: Object]}): ApolloError
 
-Creates and returns an error class with the given `name` and `message`, optionally initialized with the given `data` and `options`.  `data` passed to `createError` will later be merged with any data passed to the constructor.
+Creates and returns an error class with the given `name` and `message`, optionally initialized with the given `data`, `internalData` and `options`.  `data` and `internalData` passed to `createError` will later be merged with any data passed to the constructor.
 
 #### Options (default):
 
@@ -103,3 +131,6 @@ If the error is a known ApolloError, returns the serialized form of said error.
 **Otherwise**, *if strict is not truthy*, returns the original error passed into formatError.
 
 **Otherwise**, *if strict is truthy*, returns null.
+
+### isInstance (error): Boolean
+Returns true if the error is an instance of an ApolloError.  Otherwise, returns false
diff --git a/circle.yml b/circle.yml
deleted file mode 100644
index 1357e3f..0000000
--- a/circle.yml
+++ /dev/null
@@ -1,14 +0,0 @@
-machine:
-  node:
-    version: 5.5.0
-
-dependencies:
-  override:
-    - make environment
-    - make dependencies
-
-test:
-  override:
-    - make lint
-    - make
-    - make test
diff --git a/dist/index.d.ts b/dist/index.d.ts
new file mode 100644
index 0000000..eb2549e
--- /dev/null
+++ b/dist/index.d.ts
@@ -0,0 +1,35 @@
+import ExtendableError from 'extendable-error';
+export interface ErrorConfig {
+    message: string;
+    time_thrown?: string;
+    data?: object;
+    internalData?: object;
+    options?: {
+        showPath?: boolean;
+        showLocations?: boolean;
+    };
+}
+export interface ErrorInfo {
+    message: string;
+    name: string;
+    time_thrown: string;
+    data?: object;
+    path?: string;
+    locations?: any;
+}
+export declare class ApolloError extends ExtendableError {
+    name: string;
+    message: string;
+    time_thrown: string;
+    data: object;
+    internalData: object;
+    path: any;
+    locations: any;
+    _showLocations: boolean;
+    _showPath: boolean;
+    constructor(name: string, config: ErrorConfig, ctorConfig: ErrorConfig);
+    serialize(): ErrorInfo;
+}
+export declare const isInstance: (e: any) => boolean;
+export declare const createError: (name: string, config: ErrorConfig) => any;
+export declare const formatError: (error: any, returnNull?: boolean) => ErrorInfo;
diff --git a/dist/index.js b/dist/index.js
index 66fc43e..a63302d 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -1,129 +1,102 @@
-'use strict';
-
-Object.defineProperty(exports, "__esModule", {
-  value: true
-});
-exports.formatError = exports.createError = undefined;
-
-var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();
-
-var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
-
-var _es6Error = require('es6-error');
-
-var _es6Error2 = _interopRequireDefault(_es6Error);
-
-function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
-
-function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
-
-function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }
-
-function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }
-
-var errorMap = new Map();
-
-var DELIMITER = '/::/';
-
-var serializeName = function serializeName() {
-  var arr = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : [];
-  return arr.reduce(function (str, val) {
-    return '' + (str.length > 0 ? str + DELIMITER : str) + (val.toString ? val.toString() : val);
-  }, '');
-};
-var deserializeName = function deserializeName() {
-  var name = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : '';
-  return name.split(DELIMITER);
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
 };
-
-var ApolloError = function (_ExtendableError) {
-  _inherits(ApolloError, _ExtendableError);
-
-  function ApolloError(name, _ref) {
-    var message = _ref.message,
-        _ref$time_thrown = _ref.time_thrown,
-        time_thrown = _ref$time_thrown === undefined ? new Date().toISOString() : _ref$time_thrown,
-        _ref$data = _ref.data,
-        data = _ref$data === undefined ? {} : _ref$data,
-        _ref$options = _ref.options,
-        options = _ref$options === undefined ? {} : _ref$options;
-
-    _classCallCheck(this, ApolloError);
-
-    var t = arguments[2] && arguments[2].thrown_at || time_thrown;
-    var d = Object.assign({}, data, arguments[2] && arguments[2].data || {});
-    var m = arguments[2] && arguments[2].message || message;
-    var opts = Object.assign({}, options, arguments[2] && arguments[2].options || {});
-
-    var _this = _possibleConstructorReturn(this, (ApolloError.__proto__ || Object.getPrototypeOf(ApolloError)).call(this, serializeName([name, t, Object.assign({}, d, {
-      toString: function toString() {
-        return JSON.stringify(d);
-      }
-    })])));
-
-    _this._name = name;
-    _this._humanized_message = m || '';
-    _this._time_thrown = t;
-    _this._data = d;
-    _this._locations = opts.showLocations && arguments[2] && arguments[2].locations;
-    _this._path = opts.showPath && arguments[2] && arguments[2].path;
-    return _this;
-  }
-
-  _createClass(ApolloError, [{
-    key: 'serialize',
-    value: function serialize() {
-      var name = this._name;
-      var message = this._humanized_message;
-      var time_thrown = this._time_thrown;
-      var data = this._data;
-      var locations = this._locations;
-      var path = this._path;
-      var error = {
-        message: message,
-        name: name,
-        time_thrown: time_thrown,
-        data: data
-      };
-      if (locations) error.locations = locations;
-      if (path) error.path = path;
-      return error;
+Object.defineProperty(exports, "__esModule", { value: true });
+var assert = require("assert");
+var extendable_error_1 = require("extendable-error");
+var isString = function (d) { return Object.prototype.toString.call(d) === '[object String]'; };
+var isObject = function (d) { return Object.prototype.toString.call(d) === '[object Object]'; };
+var ApolloError = /** @class */ (function (_super) {
+    __extends(ApolloError, _super);
+    // NOTE: The object passed to the Constructor is actually `ctorData`.
+    //       We are binding the constructor to the name and config object
+    //       for the first two parameters inside of `createError`
+    function ApolloError(name, config, ctorConfig) {
+        var _this = _super.call(this, (ctorConfig && ctorConfig.message) || (config && config.message) || '') || this;
+        _this._showLocations = false;
+        _this._showPath = false;
+        var t = (ctorConfig && ctorConfig.time_thrown) || (config && config.time_thrown) || (new Date()).toISOString();
+        var m = (ctorConfig && ctorConfig.message) || (config && config.message) || '';
+        var ctorData = (ctorConfig && ctorConfig.data) || {};
+        var ctorInternalData = (ctorConfig && ctorConfig.internalData) || {};
+        var configData = (config && config.data) || {};
+        var configInternalData = (config && config.internalData) || {};
+        var d = __assign({}, _this.data, configData, ctorData);
+        var id = __assign({}, _this.internalData, configInternalData, ctorInternalData);
+        var ctorOptions = (ctorConfig && ctorConfig.options) || {};
+        var configOptions = (config && config.options) || {};
+        var opts = __assign({}, configOptions, ctorOptions);
+        _this.name = name;
+        _this.message = m;
+        _this.time_thrown = t;
+        _this.data = d;
+        _this.internalData = id;
+        _this._showLocations = !!opts.showLocations;
+        _this._showPath = !!opts.showPath;
+        return _this;
     }
-  }]);
-
-  return ApolloError;
-}(_es6Error2.default);
-
-var createError = exports.createError = function createError(name) {
-  var data = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : { message: 'An error has occurred', options: options };
-
-  var e = ApolloError.bind(null, name, data);
-  errorMap.set(name, e);
-  return e;
+    ApolloError.prototype.serialize = function () {
+        var _a = this, name = _a.name, message = _a.message, time_thrown = _a.time_thrown, data = _a.data, _showLocations = _a._showLocations, _showPath = _a._showPath, path = _a.path, locations = _a.locations;
+        var error = {
+            message: message,
+            name: name,
+            time_thrown: time_thrown,
+            data: data,
+            path: path,
+            locations: locations
+        };
+        if (_showLocations) {
+            error.locations = locations;
+        }
+        if (_showPath) {
+            error.path = path;
+        }
+        return error;
+    };
+    return ApolloError;
+}(extendable_error_1.default));
+exports.ApolloError = ApolloError;
+exports.isInstance = function (e) { return e instanceof ApolloError; };
+exports.createError = function (name, config) {
+    assert(isObject(config), 'createError requires a config object as the second parameter');
+    assert(isString(config.message), 'createError requires a "message" property on the config object passed as the second parameter');
+    // NOTE: The first two parameters give to the constructor will always be name and config
+    //       Parameters passed to the constructor when `new` is invoked will be passed as
+    //       subsequent parameters.
+    return ApolloError.bind(null, name, config);
 };
-
-var formatError = exports.formatError = function formatError(originalError) {
-  var returnNull = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
-
-  var _deserializeName = deserializeName(originalError.message),
-      _deserializeName2 = _slicedToArray(_deserializeName, 3),
-      name = _deserializeName2[0],
-      thrown_at = _deserializeName2[1],
-      d = _deserializeName2[2];
-
-  var locations = originalError.locations,
-      path = originalError.path;
-
-  var data = d !== undefined ? JSON.parse(d) : {};
-  if (!name) return returnNull ? null : originalError;
-  var CustomError = errorMap.get(name);
-  if (!CustomError) return returnNull ? null : originalError;
-  var error = new CustomError({
-    thrown_at: thrown_at,
-    data: data,
-    locations: locations,
-    path: path
-  });
-  return error.serialize();
+exports.formatError = function (error, returnNull) {
+    if (returnNull === void 0) { returnNull = false; }
+    var originalError = error ? error.originalError || error : null;
+    if (!originalError)
+        return returnNull ? null : error;
+    var name = originalError.name;
+    if (!name || !exports.isInstance(originalError))
+        return returnNull ? null : error;
+    var time_thrown = originalError.time_thrown, message = originalError.message, data = originalError.data, _showLocations = originalError._showLocations, _showPath = originalError._showPath;
+    var locations = error.locations, path = error.path;
+    if (_showLocations) {
+        originalError.locations = locations;
+    }
+    if (_showPath) {
+        originalError.path = path;
+    }
+    return originalError.serialize();
 };
 //# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/dist/index.js.map b/dist/index.js.map
index 6903d3f..5361035 100644
--- a/dist/index.js.map
+++ b/dist/index.js.map
@@ -1 +1 @@
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str + DELIMITER : str}${val.toString ? val.toString() : val}`, '');\nconst deserializeName = (name = '') => name.split(DELIMITER);\n\nclass ApolloError extends ExtendableError {\n  constructor (name, {\n    message,\n    time_thrown = (new Date()).toISOString(),\n    data = {},\n    options = {},\n  }) {\n    const t = (arguments[2] && arguments[2].thrown_at) || time_thrown;\n    const d = Object.assign({}, data, ((arguments[2] && arguments[2].data) || {}));\n    const m = (arguments[2] && arguments[2].message) || message;\n    const opts = Object.assign({}, options, ((arguments[2] && arguments[2].options) || {}));\n\n    super(serializeName([\n      name,\n      t,\n      Object.assign({}, d, {\n        toString: () => JSON.stringify(d)\n      }),\n    ]));\n\n    this._name = name;\n    this._humanized_message = m || '';\n    this._time_thrown = t;\n    this._data = d;\n    this._locations = (opts.showLocations && arguments[2] && arguments[2].locations)\n    this._path = (opts.showPath && arguments[2] && arguments[2].path);\n  }\n  serialize () {\n    const name = this._name;\n    const message = this._humanized_message;\n    const time_thrown = this._time_thrown;\n    const data = this._data;\n    const locations = this._locations;\n    const path = this._path;\n    let error = {\n      message,\n      name,\n      time_thrown,\n      data,\n    };\n    if (locations) error.locations = locations;\n    if (path) error.path = path;\n    return error;\n  }\n}\n\nexport const createError = (name, data = { message: 'An error has occurred', options }) => {\n  const e = ApolloError.bind(null, name, data);\n  errorMap.set(name, e);\n  return e;\n};\n\nexport const formatError = (originalError, returnNull = false) => {\n  const [ name, thrown_at, d ] = deserializeName(originalError.message);\n  const { locations, path } = originalError;\n  const data = d !== undefined ? JSON.parse(d) : {};\n  if (!name) return returnNull ? null : originalError;\n  const CustomError = errorMap.get(name);\n  if (!CustomError) return returnNull ? null : originalError;\n  const error = new CustomError({\n    thrown_at,\n    data,\n    locations,\n    path,\n  });\n  return error.serialize();\n};\n"]}
\ No newline at end of file
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\ No newline at end of file
diff --git a/package.json b/package.json
index a6da4c1..b2a9e70 100644
--- a/package.json
+++ b/package.json
@@ -1,40 +1,48 @@
 {
-  "name": "apollo-errors",
-  "version": "1.2.0",
-  "description": "Machine-readable custom errors for Apollostack's GraphQL server",
-  "main": "dist/index.js",
-  "scripts": {
-    "test": "make test"
-  },
-  "repository": {
-    "type": "git",
-    "url": "git+https://github.com/thebigredgeek/apollo-errors.git"
-  },
-  "keywords": [
-    "apollostack",
-    "graphql",
-    "error",
-    "api"
-  ],
-  "author": "Andrew E. Rhyne <rhyneandrew@gmail.com>",
-  "license": "MIT",
-  "bugs": {
-    "url": "https://github.com/thebigredgeek/apollo-errors/issues"
-  },
-  "homepage": "https://github.com/thebigredgeek/apollo-errors#readme",
-  "dependencies": {
-    "es6-error": "^4.0.0"
-  },
-  "devDependencies": {
-    "babel-cli": "^6.18.0",
-    "babel-core": "^6.17.0",
-    "babel-eslint": "^7.0.0",
-    "babel-preset-es2015": "^6.16.0",
-    "babel-register": "^6.18.0",
-    "chai": "^3.5.0",
-    "eslint": "^3.8.1",
-    "eslint-plugin-babel": "^3.3.0",
-    "mocha": "^3.1.2",
-    "rimraf": "^2.5.4"
-  }
+	"name": "apollo-errors",
+	"version": "1.9.0",
+	"description": "Machine-readable custom errors for Apollostack's GraphQL server",
+	"main": "dist/index.js",
+	"scripts": {
+		"test": "mocha",
+		"build": "tsc",
+		"lint": "eslint src",
+		"clean": "rimraf dist"
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/thebigredgeek/apollo-errors.git"
+	},
+	"keywords": [
+		"apollostack",
+		"graphql",
+		"apollo-server",
+		"apollo-client",
+		"error",
+		"api"
+	],
+	"author": "Andrew E. Rhyne <rhyneandrew@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/thebigredgeek/apollo-errors/issues"
+	},
+	"homepage": "https://github.com/thebigredgeek/apollo-errors#readme",
+	"dependencies": {
+		"assert": "^2.0.0",
+		"extendable-error": "^0.1.5"
+	},
+	"devDependencies": {
+		"babel-cli": "6.26.0",
+		"babel-core": "6.26.3",
+		"babel-eslint": "7.2.3",
+		"babel-preset-es2015": "6.24.1",
+		"babel-register": "6.26.0",
+		"chai": "3.5.0",
+		"eslint": "3.19.0",
+		"eslint-plugin-babel": "3.3.0",
+		"mocha": "3.5.3",
+		"rimraf": "2.6.3",
+		"typescript": "2.9.2"
+	},
+	"typings": "dist/index.d.ts"
 }
diff --git a/renovate.json b/renovate.json
new file mode 100644
index 0000000..f45d8f1
--- /dev/null
+++ b/renovate.json
@@ -0,0 +1,5 @@
+{
+  "extends": [
+    "config:base"
+  ]
+}
diff --git a/src/index.js b/src/index.js
deleted file mode 100644
index 92c1810..0000000
--- a/src/index.js
+++ /dev/null
@@ -1,76 +0,0 @@
-import ExtendableError from 'es6-error';
-
-const errorMap = new Map();
-
-const DELIMITER = '/::/';
-
-const serializeName = (arr = []) => arr.reduce((str, val) => `${str.length > 0 ? str + DELIMITER : str}${val.toString ? val.toString() : val}`, '');
-const deserializeName = (name = '') => name.split(DELIMITER);
-
-class ApolloError extends ExtendableError {
-  constructor (name, {
-    message,
-    time_thrown = (new Date()).toISOString(),
-    data = {},
-    options = {},
-  }) {
-    const t = (arguments[2] && arguments[2].thrown_at) || time_thrown;
-    const d = Object.assign({}, data, ((arguments[2] && arguments[2].data) || {}));
-    const m = (arguments[2] && arguments[2].message) || message;
-    const opts = Object.assign({}, options, ((arguments[2] && arguments[2].options) || {}));
-
-    super(serializeName([
-      name,
-      t,
-      Object.assign({}, d, {
-        toString: () => JSON.stringify(d)
-      }),
-    ]));
-
-    this._name = name;
-    this._humanized_message = m || '';
-    this._time_thrown = t;
-    this._data = d;
-    this._locations = (opts.showLocations && arguments[2] && arguments[2].locations)
-    this._path = (opts.showPath && arguments[2] && arguments[2].path);
-  }
-  serialize () {
-    const name = this._name;
-    const message = this._humanized_message;
-    const time_thrown = this._time_thrown;
-    const data = this._data;
-    const locations = this._locations;
-    const path = this._path;
-    let error = {
-      message,
-      name,
-      time_thrown,
-      data,
-    };
-    if (locations) error.locations = locations;
-    if (path) error.path = path;
-    return error;
-  }
-}
-
-export const createError = (name, data = { message: 'An error has occurred', options }) => {
-  const e = ApolloError.bind(null, name, data);
-  errorMap.set(name, e);
-  return e;
-};
-
-export const formatError = (originalError, returnNull = false) => {
-  const [ name, thrown_at, d ] = deserializeName(originalError.message);
-  const { locations, path } = originalError;
-  const data = d !== undefined ? JSON.parse(d) : {};
-  if (!name) return returnNull ? null : originalError;
-  const CustomError = errorMap.get(name);
-  if (!CustomError) return returnNull ? null : originalError;
-  const error = new CustomError({
-    thrown_at,
-    data,
-    locations,
-    path,
-  });
-  return error.serialize();
-};
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..683c776
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,122 @@
+import * as assert from 'assert';
+import ExtendableError from 'extendable-error';
+
+const isString = d => Object.prototype.toString.call(d) === '[object String]';
+const isObject = d => Object.prototype.toString.call(d) === '[object Object]';
+
+export interface ErrorConfig {
+  message: string;
+  time_thrown?: string;
+  data?: object;
+  internalData?: object;
+  options?: {
+    showPath?: boolean;
+    showLocations?: boolean;
+  };
+}
+
+export interface ErrorInfo {
+  message: string;
+  name: string;
+  time_thrown: string;
+  data?: object;
+  path?: string;
+  locations?: any;
+}
+
+export class ApolloError extends ExtendableError {
+  name: string;
+  message: string;
+  time_thrown: string;
+  data: object;
+  internalData: object;
+  path: any;
+  locations: any;
+  _showLocations: boolean = false;
+  _showPath: boolean = false;
+
+  // NOTE: The object passed to the Constructor is actually `ctorData`.
+  //       We are binding the constructor to the name and config object
+  //       for the first two parameters inside of `createError`
+  constructor(name: string, config: ErrorConfig, ctorConfig: ErrorConfig) {
+    super((ctorConfig && ctorConfig.message) || (config && config.message) || '');
+
+    const t = (ctorConfig && ctorConfig.time_thrown) || (config && config.time_thrown) || (new Date()).toISOString();
+    const m = (ctorConfig && ctorConfig.message) || (config && config.message) || '';
+    const ctorData = (ctorConfig && ctorConfig.data) || {};
+    const ctorInternalData = (ctorConfig && ctorConfig.internalData) || {}
+    const configData = (config && config.data) || {};
+    const configInternalData = (config && config.internalData) || {}
+    const d = { ...this.data, ...configData, ...ctorData };
+    const id = { ...this.internalData, ...configInternalData, ...ctorInternalData}
+    const ctorOptions = (ctorConfig && ctorConfig.options) || {};
+    const configOptions = (config && config.options) || {};
+    const opts = { ...configOptions, ...ctorOptions };
+
+
+    this.name = name;
+    this.message = m;
+    this.time_thrown = t;
+    this.data = d;
+    this.internalData = id;
+    this._showLocations = !!opts.showLocations;
+    this._showPath = !!opts.showPath;
+  }
+
+  serialize(): ErrorInfo {
+    const { name, message, time_thrown, data, _showLocations, _showPath, path, locations } = this;
+
+    let error: ErrorInfo = {
+      message,
+      name,
+      time_thrown,
+      data,
+      path,
+      locations
+    };
+
+    if (_showLocations) {
+      error.locations = locations;
+    }
+
+    if (_showPath) {
+      error.path = path;
+    }
+
+    return error;
+  }
+}
+
+export const isInstance = e => e instanceof ApolloError;
+
+export const createError = (name: string, config: ErrorConfig) => {
+  assert(isObject(config), 'createError requires a config object as the second parameter');
+  assert(isString(config.message), 'createError requires a "message" property on the config object passed as the second parameter');
+  // NOTE: The first two parameters give to the constructor will always be name and config
+  //       Parameters passed to the constructor when `new` is invoked will be passed as
+  //       subsequent parameters.
+  return ApolloError.bind(null, name, config);
+};
+
+export const formatError = (error, returnNull = false): ErrorInfo => {
+  const originalError = error ? error.originalError || error : null;
+
+  if (!originalError) return returnNull ? null : error;
+
+  const { name } = originalError;
+
+  if (!name || !isInstance(originalError)) return returnNull ? null : error;
+
+  const { time_thrown, message, data, _showLocations, _showPath } = originalError;
+  const { locations, path } = error;
+
+  if (_showLocations) {
+    originalError.locations = locations;
+  }
+
+  if (_showPath) {
+    originalError.path = path;
+  }
+
+  return originalError.serialize();
+};
diff --git a/test/spec.js b/test/spec.js
index 7b632e4..4b2df72 100644
--- a/test/spec.js
+++ b/test/spec.js
@@ -1,41 +1,87 @@
 import { expect } from 'chai';
+import assert from 'assert';
 
 import { createError, formatError } from '../dist';
 
-describe('createError', () => {
-  it('returns an error that serializes properly', () => {
-    const FooError = createError('FooError', {
-      message: 'A foo error has occurred',
-      data: {
-        hello: 'world'
-      },
-      options: {
-        showLocations: false,
-        showPath: true,
-      },
-    });
+const { AssertionError } = assert;
 
-    const iso = new Date().toISOString();
+describe('createError', () => {
+  context('when properly used', () => {
+    it('returns an error that serializes properly', () => {
+      const FooError = createError('FooError', {
+        message: 'A foo error has occurred',
+        data: {
+          hello: 'world'
+        },
+        options: {
+          showLocations: false,
+          showPath: true,
+        },
+      });
+      const iso = new Date().toISOString();
+      const e = new FooError({
+        message: 'A foo 2.0 error has occurred',
+        data: {
+          hello: 'world',
+          foo: 'bar'
+        },
+        options: {
+          showLocations: true,
+          showPath: false,
+        },
+      });
 
-    const e = new FooError({
-      message: 'A foo 2.0 error has occurred',
-      data: {
+      const { message, name, time_thrown, data } = e.serialize();
+      expect(message).to.equal('A foo 2.0 error has occurred');
+      expect(name).to.equal('FooError');
+      expect(time_thrown).to.equal(e.time_thrown);
+      expect(data).to.eql({
+        hello: 'world',
         foo: 'bar'
-      },
-      options: {
-        showLocations: true,
-        showPath: false,
-      },
+      });
     });
+    it('uses original message and merges original data', () => {
+      const FooError = createError('FooError', {
+        message: 'A foo error has occurred',
+        data: {
+          hello: 'world'
+        },
+        options: {
+          showLocations: false,
+          showPath: true
+        }
+      });
+      const e = new FooError({data: {foo: 'bar'}});
 
-    const { message, name, time_thrown, data } = e.serialize();
+      const { message, name, time_thrown, data } = e.serialize();
+      expect(message).to.equal('A foo error has occurred');
+      expect(name).to.equal('FooError');
+      expect(time_thrown).to.equal(e.time_thrown);
+      expect(data).to.eql({ hello: 'world', foo: 'bar' });
+    });
+  });
+  context('when missing a config as the second parameter', () => {
+    it('throws an assertion error with a useful message', () => {
+      try {
+        createError('FooError');
+        throw new Error('did not throw as expected');
+      } catch (err) {
+        expect(err instanceof AssertionError).to.be.true;
+        expect(err.message).to.equal('createError requires a config object as the second parameter');
+      }
+    });
+  });
+  context('when missing a message from the config object passed as the second parameter', () => {
+    it('throws an assertion error with a useful message', () => {
+      try {
+        createError('FooError', {
 
-    expect(message).to.equal('A foo 2.0 error has occurred');
-    expect(name).to.equal('FooError');
-    expect(time_thrown).to.equal(e._time_thrown);
-    expect(data).to.eql({
-      hello: 'world',
-      foo: 'bar'
+        });
+        throw new Error('did not throw as expected');
+      } catch (err) {
+        expect(err instanceof AssertionError).to.be.true;
+        expect(err.message).to.equal('createError requires a "message" property on the config object passed as the second parameter')
+      }
     });
   });
 });
@@ -55,13 +101,13 @@ describe('formatError', () => {
         });
 
         const e = new FooError({
+          message: 'A foo 2.0 error has occurred',
           data: {
             oh: 'shit'
           }
         });
-
         const s = formatError({
-          message: e.message
+          originalError: e
         }, false);
 
         expect(s).to.eql(e.serialize());
@@ -84,11 +130,28 @@ describe('formatError', () => {
         const e = new FooError();
 
         const s = formatError({
-          message: e.message
+          originalError: e
         }, true);
 
         expect(s).to.eql(e.serialize());
       });
     });
   });
+  context('error has internalData', () => {
+    it('does not include the internalData property', () => {
+      const FooError = createError('FooError', {
+        message: 'A foo error has occurred',
+        internalData: {
+          secret: 'SQL ERROR'
+        }
+      });
+
+      const e = new FooError();
+      expect(e.internalData).to.to.eql({
+        secret: 'SQL ERROR'
+      })
+      const s = formatError(e);
+      expect(s.internalData).to.eq(undefined)
+    })
+  })
 });
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..a84597b
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "sourceMap": true,
+    "removeComments": false,
+    "noImplicitAny": false,
+    "outDir": "./dist",
+    "declaration": true
+  },
+  "include": [
+    "./src/**/*"
+  ]
+}