diff --git a/src/common/TesseractWorker.js b/src/common/TesseractWorker.js
index 063f44f..25db027 100644
--- a/src/common/TesseractWorker.js
+++ b/src/common/TesseractWorker.js
@@ -1,39 +1,82 @@
+/**
+ *
+ * The core part of tesseract.js to execute the OCR jobs.
+ *
+ * @fileoverview Worker for OCR jobs
+ * @author Kevin Kwok <antimatter15@gmail.com>
+ * @author Guillermo Webster <gui@mit.edu>
+ * @author Jerome Wu <jeromewus@gmail.com>
+ */
 const check = require('check-types');
 const adapter = require('../node');
 const circularize = require('./circularize');
 const TesseractJob = require('./TesseractJob');
 
+/**
+ * TesseractWorker
+ * @name TesseractWorker
+ * @function execute TesseractJob with a queue mechanism
+ * @access public
+ */
 class TesseractWorker {
-  constructor(workerOptions = {}) {
+  /**
+   * constructor
+   *
+   * @name constructor
+   * @function initialize the worker
+   * @access public
+   * @param {object} options - worker configurations
+   * @param {string} options.workerPath -
+   *     A remote path to load worker script.
+   *     In browser-like environment, it is downloaded from a CDN service.
+   *     Please update this option if you self-host the worker script.
+   *     In Node.js environment, this option is not used as the worker script is in local.
+   * @param {string} options.corePath -
+   *     A remote path to load tesseract.js-core script.
+   *     In browser-like environment, it is downloaded from a CDN service.
+   *     Please update this option if you self-host the core script.
+   *     In Node.js environment, this option is not used as the core script is in local.
+   * @param {string} options.langPath -
+   *     A remote path to load *.traineddata.gz, it is download from a CDN service.
+   *     Please update this option if you self-host the worker script.
+   * @param {string} [options.cachePath=.] - @see {@link https://github.com/jeromewu/tesseract.js-utils/blob/master/src/loadLang.js}
+   * @param {string} [options.cacheMethod=write] - @see {@link https://github.com/jeromewu/tesseract.js-utils/blob/master/src/loadLang.js}
+   * @param {string} [options.dataPath=.] - @see {@link https://github.com/jeromewu/tesseract.js-utils/blob/master/src/loadLang.js}
+   *
+   */
+  constructor(options = {}) {
     this.worker = null;
-    this.workerOptions = Object.assign({}, adapter.defaultOptions, workerOptions);
+    this.options = {
+      ...adapter.defaultOptions,
+      ...options,
+    };
     this._currentJob = null;
     this._queue = [];
   }
 
-  recognize(image, options = { lang: 'eng' }) {
+  recognize(image, lang = 'eng', params = {}) {
     return this._delay((job) => {
       job._send(
         'recognize',
         {
           image,
-          options: check.string(options)
-            ? { lang: options || 'eng' }
-            : options,
-          workerOptions: this.workerOptions,
+          lang,
+          params,
+          options: this.options,
         },
       );
     });
   }
 
-  detect(image, options = {}) {
+  detect(image, params = {}) {
     return this._delay((job) => {
       job._send(
         'detect',
         {
           image,
-          options,
-          workerOptions: this.workerOptions,
+          lang: 'osd',
+          params,
+          options: this.options,
         },
       );
     });
@@ -50,7 +93,7 @@ class TesseractWorker {
 
   _delay(fn) {
     if (check.null(this.worker)) {
-      this.worker = adapter.spawnWorker(this, this.workerOptions);
+      this.worker = adapter.spawnWorker(this, this.options);
     }
 
     const job = new TesseractJob(this);
diff --git a/src/common/worker.js b/src/common/worker.js
index 441c486..50faf0d 100644
--- a/src/common/worker.js
+++ b/src/common/worker.js
@@ -23,7 +23,7 @@ const setImage = (image) => {
 const handleInit = (req, res) => {
   let MIN_MEMORY = 100663296;
 
-  if (['chi_sim', 'chi_tra', 'jpn'].includes(req.options.lang)) {
+  if (['chi_sim', 'chi_tra', 'jpn'].includes(req.lang)) {
     MIN_MEMORY = 167772160;
   }
 
@@ -49,8 +49,8 @@ const handleInit = (req, res) => {
 };
 
 const loadLanguage = ({
-  options: { lang },
-  workerOptions: {
+  lang,
+  options: {
     langPath, cachePath, cacheMethod, dataPath,
   },
 }) => (
@@ -69,18 +69,18 @@ const handleRecognize = (req, res) => (
     .then(() => (
       loadLanguage(req)
         .then(() => {
-          const { options } = req;
+          const { image, lang, params } = req;
           const progressUpdate = (progress) => {
             res.progress({ status: 'initializing api', progress });
           };
           progressUpdate(0);
-          base.Init(null, options.lang);
+          base.Init(null, lang);
           progressUpdate(0.3);
-          Object.keys(options).forEach((key) => {
-            base.SetVariable(key, options[key]);
+          Object.keys(params).forEach((key) => {
+            base.SetVariable(key, params[key]);
           });
           progressUpdate(0.6);
-          const ptr = setImage(req.image);
+          const ptr = setImage(image);
           progressUpdate(1);
           base.Recognize(null);
           const result = dump(Module, base);
@@ -95,12 +95,13 @@ const handleRecognize = (req, res) => (
 const handleDetect = (req, res) => (
   handleInit(req, res)
     .then(() => (
-      loadLanguage({ ...req, options: { ...req.options, lang: 'osd' } })
+      loadLanguage(req)
         .then(() => {
-          base.Init(null, 'osd');
+          const { image, lang } = req;
+          base.Init(null, lang);
           base.SetPageSegMode(Module.PSM_OSD_ONLY);
 
-          const ptr = setImage(req.image);
+          const ptr = setImage(image);
           const results = new Module.OSResults();
 
           if (!base.DetectOS(results)) {
diff --git a/src/index.js b/src/index.js
index 4db7640..71bc77e 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,7 +1,18 @@
+/**
+ *
+ * Entry point for tesseract.js, should be the entry when bundling.
+ *
+ * @fileoverview entry point for tesseract.js
+ * @author Kevin Kwok <antimatter15@gmail.com>
+ * @author Guillermo Webster <gui@mit.edu>
+ * @author Jerome Wu <jeromewus@gmail.com>
+ */
 const utils = require('tesseract.js-utils');
 const TesseractWorker = require('./common/TesseractWorker');
 
 module.exports = {
+  /** Worker for OCR, @see common/TesseractWorker.js */
   TesseractWorker,
+  /** Utilities for tesseract.js, @see {@link https://www.npmjs.com/package/tesseract.js-utils} */
   utils,
 };