Update folder structure and refactor

5 years ago · 97fa545936
46 changed files with 632 additions and 998 deletions
--- a/examples/node/recognize.js
+++ b/examples/node/recognize.js
@ -1,6 +1,8 @@
 #!/usr/bin/env node
 const path = require('path');
-const { createScheduler, createWorker, createJob, OEM } = require('../../');
+const {
  createScheduler, createWorker, createJob, PSM,
 } = require('../../');
 const [,, imagePath] = process.argv;
 const image = path.resolve(__dirname, (imagePath || '../../tests/assets/images/cosmic.png'));
@ -11,12 +13,18 @@ console.log(`Recognizing ${image}`);
  const scheduler = createScheduler();
  const worker = createWorker();
  await worker.load();
-  await worker.loadLanguage('osd');
+  await worker.loadLanguage('eng');
-  await worker.initialize('osd', {
+  await worker.initialize('eng');
-    tessedit_ocr_engine_mode: OEM.OSD_ONLY,
+  await worker.setParameters({
    tessedit_char_whitelist: 'ABCDEFGH',
  });
  scheduler.addWorker(worker);
-  const data = await scheduler.addJob(createJob('detect', { image }));
+  const { text: t1 } = await scheduler.addJob(createJob('recognize', { image }));
-  console.log(data);
+  console.log(t1);
  await worker.setParameters({
    tessedit_char_whitelist: 'abcdefg',
  });
  const { text: t2 } = await scheduler.addJob(createJob('recognize', { image }));
  console.log(t2);
  scheduler.terminate();
 })();
--- a/package-lock.json
+++ b/package-lock.json
@ -8548,9 +8548,9 @@
      }
    },
    "tesseract.js-core": {
-      "version": "2.0.0-beta.12",
+      "version": "2.0.0-beta.13",
-      "resolved": "https://registry.npmjs.org/tesseract.js-core/-/tesseract.js-core-2.0.0-beta.12.tgz",
+      "resolved": "https://registry.npmjs.org/tesseract.js-core/-/tesseract.js-core-2.0.0-beta.13.tgz",
-      "integrity": "sha512-/CJhrDO82u1Nix4BQXYdL98+ctPZK4ZBYIiPlVu9uu9DHH65HsTEUV86Kd/3hdg67wCPmO1FzRGOaskvLv5O5A=="
+      "integrity": "sha512-GboWV/aV5h+Whito6L6Q3WCFZ2+lgxZGgjY84wSpWbTLEkkZgHsU+dz1or+3rWSABH/nuzHDco1bZRk5+f94mw=="
    },
    "tesseract.js-utils": {
      "version": "1.0.0-beta.8",
--- a/package.json
+++ b/package.json
@ -57,7 +57,7 @@
    "is-url": "1.2.2",
    "opencollective-postinstall": "^2.0.2",
    "resolve-url": "^0.2.1",
-    "tesseract.js-core": "^2.0.0-beta.12",
+    "tesseract.js-core": "^2.0.0-beta.13",
    "tesseract.js-utils": "^1.0.0-beta.8"
  },
  "repository": {
--- a/scripts/webpack.config.dev.js
+++ b/scripts/webpack.config.dev.js
@ -21,7 +21,7 @@ const genConfig = ({
    }),
  ],
  devServer: {
-      allowedHosts: ['localhost', '.gitpod.io'],
+    allowedHosts: ['localhost', '.gitpod.io'],
  },
 });
--- a/src/common/TesseractJob.js
+++ b/src/common/TesseractJob.js
@ -1,163 +0,0 @@
 /**
 *
 * The job exectued by worker, each job is basically a recognition of an image.
 *
 * @fileoverview Job excuted by Worker
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 const adapter = require('../node/');
 /** A global job counter as part of job id */
 let jobCounter = 0;
 class TesseractJob {
  /**
   * constructor
   *
   * @name constructor
   * @function initial a TesseractJob
   * @access public
   * @param {object} worker - An instance of TesseractWorker
   */
  constructor(worker) {
    jobCounter += 1;
    this.id = `Job-${jobCounter}-${Math.random().toString(16).slice(3, 8)}`;
    this._worker = worker;
    /**
     * As all the callback functions are saved in an array.
     * Basically you can register more than callback function
     * for then, catch, progress and finally.
     */
    this._resolve = [];
    this._reject = [];
    this._progress = [];
    this._finally = [];
  }
  /**
   * then
   *
   * @name then
   * @function A function to chain like Promise
   * @access public
   * @param {function} resolve - called when the job succeeds
   * @param {function} reject - called when the job fails
   */
  then(resolve, reject) {
    return new Promise((res, rej) => {
      if (!this._resolve.push) {
        res(this._result);
      } else {
        this._resolve.push(res);
      }
      this.catch(rej);
    }).then(resolve, reject);
  }
  /**
   * catch
   *
   * @name catch
   * @function register a function to call when there is an error
   * @access public
   * @param {function} reject - callback function for error
   */
  catch(reject) {
    if (this._reject.push) {
      this._reject.push(reject);
    } else {
      reject(this._reject);
    }
    return this;
  }
  /**
   * progress
   *
   * @name progress
   * @function register a function to show progress of the recognition,
   *   use res.progress to print the message
   * @access public
   * @param {function} fn - callback function for progress information
   */
  progress(fn) {
    this._progress.push(fn);
    return this;
  }
  /**
   * finally
   *
   * @name finally
   * @function registry a callback function for final
   * @access public
   * @param {function} fn - callback function for final
   */
  finally(fn) {
    this._finally.push(fn);
    return this;
  }
  /**
   * send
   *
   * @name send
   * @function send specific action with payload a worker
   * @access public
   * @param {string} action - action to trigger, should be "recognize" or "detect"
   * @param {object} payload - data to be consumed
   */
  send(action, payload) {
    adapter.sendPacket(this._worker, {
      jobId: this.id,
      action,
      payload,
    });
  }
  /**
   * handle
   *
   * @name handle
   * @function execute packet action
   * @access public
   * @param {object} packet action and payload to handle
   */
  handle(packet) {
    const { data } = packet;
    let runFinallyCbs = false;
    if (packet.status === 'resolve') {
      if (this._resolve.length === 0) console.log(data);
      this._resolve.forEach((fn) => {
        const ret = fn(data);
        if (ret && typeof ret.then === 'function') {
          console.warn('TesseractJob instances do not chain like ES6 Promises. To convert it into a real promise, use Promise.resolve.');
        }
      });
      this._resolve = data;
      this._worker.dequeue();
      runFinallyCbs = true;
    } else if (packet.status === 'reject') {
      if (this._reject.length === 0) console.error(data);
      this._reject.forEach(fn => fn(data));
      this._reject = data;
      this._worker.dequeue();
      runFinallyCbs = true;
    } else if (packet.status === 'progress') {
      this._progress.forEach(fn => fn(data));
    } else {
      console.warn('Message type unknown', packet.status);
    }
    if (runFinallyCbs) {
      this._finally.forEach(fn => fn(data));
    }
  }
 }
 module.exports = TesseractJob;
--- a/src/common/TesseractWorker.js
+++ b/src/common/TesseractWorker.js
@ -1,196 +0,0 @@
 /**
 *
 * 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 resolveURL = (typeof window !== 'undefined' && typeof window.document !== 'undefined') ? require('resolve-url') : s => s;
 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
   *
   * @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 {boolean} [options.workerBlobURL=true] - Use a blob: URL for the worker script
   * @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.options = {
      ...adapter.defaultOptions,
      ...options,
    };
    ['corePath', 'workerPath', 'langPath'].forEach((key) => {
      if (check.not.undefined(options[key])) {
        this.options = { ...this.options, [key]: resolveURL(options[key]) };
      }
    });
    this._currentJob = null;
    this._queue = [];
  }
  /**
   * recognize
   *
   * @name recognize
   * @function recognize text in given image
   * @access public
   * @param {Buffer, string} image - image to be recognized
   * @param {string, array} [langs=eng] - languages to recognize
   * @param {object} params - tesseract parameters
   *
   */
  recognize(image, langs = 'eng', params = {}) {
    return this._sendJob('recognize', image, langs, params);
  }
  /**
   * detect
   *
   * @name detect
   * @function detect language of the text in the image
   * @access public
   * @param {Buffer, string} image - image to be recognized
   * @param {object} params - tesseract parameters
   *
   */
  detect(image, params = {}) {
    return this._sendJob('detect', image, 'osd', params);
  }
  /**
   * recv
   *
   * @name recv
   * @function handle completed job
   * @access public
   * @param {object} packet job data
   */
  recv(packet) {
    if (this._currentJob.id === packet.jobId) {
      this._currentJob.handle({
        ...packet,
        data: packet.status === 'resolve' && packet.action === 'recognize'
          ? circularize(packet.data)
          : packet.data,
      });
    } else {
      console.warn(`Job ID ${packet.jobId} not known.`);
    }
  }
  /**
   * dequeue
   *
   * @name dequeue
   * @function dequeue and execute the rear job
   * @access public
   */
  dequeue() {
    this._currentJob = null;
    if (this._queue.length) {
      this._queue[0]();
    }
  }
  /**
   * terminate
   *
   * @name terminate
   * @function terminate the worker
   * @access public
   *
   */
  terminate() {
    if (this.worker) {
      adapter.terminateWorker(this);
    }
    this.worker = null;
    this._currentJob = null;
    this._queue = [];
  }
  /**
   * _sendJob
   *
   * @name _sendJob
   * @function append a new job to the job queue
   * @access private
   * @param {string} type job type, should be recognize or detect
   * @param {Buffer, string} image image to recognize
   * @param {string} lang language to recognize
   * @param {object} params tesseract parameters
   */
  _sendJob(type, image, langs, params) {
    return this._delay((job) => {
      job.send(
        type,
        {
          image,
          langs,
          params,
          options: this.options,
        },
      );
    });
  }
  /**
   * _delay
   *
   * @name _delay
   * @function delays the fn to execute until it is on the rear of the queue
   * @access private
   * @param {function} fn A handler function for the job
   */
  _delay(fn) {
    if (check.null(this.worker)) {
      this.worker = adapter.spawnWorker(this, this.options);
    }
    const job = new TesseractJob(this);
    this._queue.push(() => {
      this._queue.shift();
      this._currentJob = job;
      fn(job);
    });
    if (check.null(this._currentJob)) {
      this.dequeue();
    }
    return job;
  }
 }
 module.exports = TesseractWorker;
--- a/src/common/circularize.js
+++ b/src/common/circularize.js
@ -1,86 +0,0 @@
 /**
 * The result of dump.js is a big JSON tree
 * which can be easily serialized (for instance
 * to be sent from a webworker to the main app
 * or through Node's IPC), but we want
 * a (circular) DOM-like interface for walking
 * through the data.
 *
 * @fileoverview DOM-like interface for walking through data
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 module.exports = (iPage) => {
  const page = {
    ...iPage,
    paragraphs: [],
    lines: [],
    words: [],
    symbols: [],
  };
  page.blocks.forEach((iBlock) => {
    const block = {
      ...iBlock,
      page,
      lines: [],
      words: [],
      symbols: [],
    };
    block.paragraphs.forEach((iPara) => {
      const para = {
        ...iPara,
        block,
        page,
        words: [],
        symbols: [],
      };
      para.lines.forEach((iLine) => {
        const line = {
          ...iLine,
          paragraph: para,
          block,
          page,
          symbols: [],
        };
        line.words.forEach((iWord) => {
          const word = {
            ...iWord,
            line,
            paragraph: para,
            block,
            page,
          };
          word.symbols.forEach((iSym) => {
            const sym = {
              ...iSym,
              word,
              line,
              paragraph: para,
              block,
              page,
            };
            sym.line.symbols.push(sym);
            sym.paragraph.symbols.push(sym);
            sym.block.symbols.push(sym);
            sym.page.symbols.push(sym);
          });
          word.paragraph.words.push(word);
          word.block.words.push(word);
          word.page.words.push(word);
        });
        line.block.lines.push(line);
        line.page.lines.push(line);
      });
      para.page.paragraphs.push(para);
    });
  });
  return page;
 };
--- a/src/common/createWorker.js
+++ b/src/common/createWorker.js
@ -1,129 +0,0 @@
 const { isBrowser } = require('./env');
 const resolveURL = isBrowser ? require('resolve-url') : s => s; // eslint-disable-line
 const circularize = require('./circularize');
 const createJob = require('./createJob');
 const { defaultParams } = require('./options');
 const {
  defaultOptions,
  spawnWorker,
  terminateWorker,
  setOnMessage,
 } = require('../node');
 let workerCounter = 0;
 const resolvePaths = (options) => {
  const opts = { ...options };
  ['corePath', 'workerPath', 'langPath'].forEach((key) => {
    if (typeof options[key] !== 'undefined') {
      opts[key] = resolveURL(opts[key]);
    }
  });
  return opts;
 };
 module.exports = (options = {}) => {
  workerCounter += 1;
  const id = `Worker-${workerCounter}-${Math.random().toString(16).slice(3, 8)}`;
  const opts = resolvePaths({
    ...defaultOptions,
    ...options,
  });
  const { logger } = opts;
  const resolves = {};
  const rejects = {};
  let worker = spawnWorker(opts);
  const setResolve = (action, res) => {
    resolves[action] = res;
  };
  const setReject = (action, rej) => {
    rejects[action] = rej;
  };
  const load = () => (
    new Promise((resolve, reject) => {
      const job = createJob(
        'load',
        opts,
      );
      setResolve('load', resolve);
      setReject('load', reject);
      job.start({ worker, id });
    })
  );
  const loadLanguage = (langs = 'eng') => (
    new Promise((resolve, reject) => {
      const job = createJob(
        'load-language',
        {
          langs,
          options: opts,
        },
      );
      setResolve('load-language', resolve);
      setReject('load-language', reject);
      job.start({ worker, id });
    })
  );
  const initialize = (langs = 'eng', params = {}) => (
    new Promise((resolve, reject) => {
      const job = createJob(
        'initialize',
        {
          langs,
          params: {
            ...defaultParams,
            ...params,
          },
        },
      );
      setResolve('initialize', resolve);
      setReject('initialize', reject);
      job.start({ worker, id });
    })
  );
  const terminate = () => {
    if (worker !== null) {
      terminateWorker({ worker });
      worker = null;
    }
  };
  setOnMessage(worker, (packet) => {
    const { status, action, data } = packet;
    if (status === 'resolve') {
      if (action === 'load') {
        resolves.load(data);
      } else if (action === 'initialize') {
        resolves.initialize({ id });
      } else if (action === 'load-language') {
        resolves['load-language'](data);
      } else if (action === 'recognize') {
        resolves.recognize(circularize(data));
      } else if (action === 'detect') {
        resolves.detect(data);
      }
    } else if (status === 'reject') {
      rejects[action](data);
      throw Error(data);
    } else if (status === 'progress') {
      logger(data);
    }
  });
  return {
    id,
    worker,
    setResolve,
    setReject,
    load,
    loadLanguage,
    initialize,
    terminate,
  };
 };
--- a/src/common/env.js
+++ b/src/common/env.js
@ -1 +0,0 @@
 exports.isBrowser = (typeof window !== 'undefined') && (typeof window.document !== 'undefined');
--- a/src/common/options.js
+++ b/src/common/options.js
@ -1,40 +0,0 @@
 const { OEM, PSM } = require('./types');
 module.exports = {
  defaultOptions: {
    /*
     * default path for downloading *.traineddata, this URL basically
     * points to a github page, not using jsDelivr as there is is limitation
     * of 20 MB.
     */
    langPath: 'https://tessdata.projectnaptha.com/4.0.0',
    /*
     * Use BlobURL for worker script by default
     */
    workerBlobURL: true,
    logger: () => {},
  },
  /*
   * default params for recognize()
   */
  defaultParams: {
    tessedit_ocr_engine_mode: OEM.LSTM_ONLY,
    tessedit_pageseg_mode: PSM.SINGLE_BLOCK,
    tessedit_char_whiltelist: '',
    tessjs_create_pdf: '0',
    tessjs_create_hocr: '1',
    tessjs_create_tsv: '1',
    tessjs_create_box: '0',
    tessjs_create_unlv: '0',
    tessjs_create_osd: '0',
    tessjs_textonly_pdf: '0',
    tessjs_pdf_name: 'tesseract.js-ocr-result',
    tessjs_pdf_title: 'Tesseract.js OCR Result',
    tessjs_pdf_auto_download: true,
    tessjs_pdf_bin: false,
    tessjs_image_rectangle_left: 0,
    tessjs_image_rectangle_top: 0,
    tessjs_image_rectangle_width: -1,
    tessjs_image_rectangle_height: -1,
  },
 };
--- a/src/common/pdf-ttf.js
+++ b/src/common/pdf-ttf.js
@ -1 +0,0 @@
 module.exports = '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';
--- a/src/common/types.js
+++ b/src/common/types.js
@ -1,34 +0,0 @@
 module.exports = {
  /*
   * OEM = OCR Engine Mode, and there are 5 possible modes.
   *
   * By default tesseract.js uses TESSERACT_LSTM_COMBINED mode, which uses LSTM when possible.
   * If you need to use some tesseract v3 features (like tessedit_char_whitelist),
   * you need to use TESSERACT_ONLY mode.
   *
   */
  OEM: {
    TESSERACT_ONLY: 0,
    LSTM_ONLY: 1,
    TESSERACT_LSTM_COMBINED: 2,
    DEFAULT: 3,
  },
  /*
   * PSM = Page Segmentation Mode
   */
  PSM: {
    OSD_ONLY: '0',
    AUTO_OSD: '1',
    AUTO_ONLY: '2',
    AUTO: '3',
    SINGLE_COLUMN: '4',
    SINGLE_BLOCK_VERT_TEXT: '5',
    SINGLE_BLOCK: '6',
    SINGLE_LINE: '7',
    SINGLE_WORD: '8',
    SINGLE_CHAR: '9',
    SPARSE_TEXT: '10',
    SPARSE_TEXT_OSD: '11',
    RAW_LINE: '12',
  },
 };
--- a/src/common/utils.js
+++ b/src/common/utils.js
@ -1,87 +0,0 @@
 const { readImage } = require('tesseract.js-utils');
 /**
 * setImage
 *
 * @name setImage
 * @function set image in tesseract for recognition
 * @access public
 * @param {array} image - binary array in array format
 * @returns {number} - an emscripten pointer of the image
 */
 exports.setImage = (TessModule, api, image, params) => {
  const {
    tessjs_image_rectangle_left: left,
    tessjs_image_rectangle_top: top,
    tessjs_image_rectangle_width: width,
    tessjs_image_rectangle_height: height,
  } = params;
  const {
    w, h, bytesPerPixel, data, pix,
  } = readImage(TessModule, Array.from(image));
  /*
   * As some image format (ex. bmp) is not supported natiely by tesseract,
   * sometimes it will not return pix directly, but data and bytesPerPixel
   * for another SetImage usage.
   *
   */
  if (data === null) {
    api.SetImage(pix);
  } else {
    api.SetImage(data, w, h, bytesPerPixel, w * bytesPerPixel);
  }
  api.SetRectangle(
    (left < 0) ? 0 : left,
    (top < 0) ? 0 : top,
    (width < 0) ? w : width,
    (height < 0) ? h : height,
  );
  return data === null ? pix : data;
 };
 exports.getLangsStr = langs => (
  typeof langs === 'string'
    ? langs
    : langs.map(lang => (typeof lang === 'string' ? lang : lang.data)).join('+')
 );
 /**
 * handleOutput
 *
 * @name handleOutput
 * @function handle file output
 * @access private
 * @param {object} customParams - an object of params
 */
 exports.getFiles = (TessModule, api, adapter, params) => {
  let files = {};
  const {
    tessjs_create_pdf,
    tessjs_textonly_pdf,
    tessjs_pdf_name,
    tessjs_pdf_title,
    tessjs_pdf_auto_download,
    tessjs_pdf_bin,
  } = params;
  if (tessjs_create_pdf === '1') {
    const pdfRenderer = new TessModule.TessPDFRenderer(tessjs_pdf_name, '/', tessjs_textonly_pdf === '1');
    pdfRenderer.BeginDocument(tessjs_pdf_title);
    pdfRenderer.AddImage(api);
    pdfRenderer.EndDocument();
    TessModule._free(pdfRenderer);
    const data = TessModule.FS.readFile(`/${tessjs_pdf_name}.pdf`);
    if (tessjs_pdf_bin) {
      files = { pdf: data, ...files };
    }
    if (tessjs_pdf_auto_download) {
      adapter.writeFile(`${tessjs_pdf_name}.pdf`, data, 'application/pdf');
    }
  }
  return files;
 };
--- a/src/constants/OEM.js
+++ b/src/constants/OEM.js
@ -0,0 +1,12 @@
 /*
 * OEM = OCR Engine Mode, and there are 4 possible modes.
 *
 * By default tesseract.js uses LSTM_ONLY mode.
 *
 */
 module.exports = {
  TESSERACT_ONLY: 0,
  LSTM_ONLY: 1,
  TESSERACT_LSTM_COMBINED: 2,
  DEFAULT: 3,
 };
--- a/src/constants/PSM.js
+++ b/src/constants/PSM.js
@ -0,0 +1,18 @@
 /*
 * PSM = Page Segmentation Mode
 */
 module.exports = {
  OSD_ONLY: '0',
  AUTO_OSD: '1',
  AUTO_ONLY: '2',
  AUTO: '3',
  SINGLE_COLUMN: '4',
  SINGLE_BLOCK_VERT_TEXT: '5',
  SINGLE_BLOCK: '6',
  SINGLE_LINE: '7',
  SINGLE_WORD: '8',
  CIRCLE_WORD: '9',
  SINGLE_CHAR: '10',
  SPARSE_TEXT: '11',
  SPARSE_TEXT_OSD: '12',
 };
--- a/src/constants/config.js
+++ b/src/constants/config.js
@ -0,0 +1,5 @@
 const OEM = require('./OEM');
 module.exports = {
  defaultOEM: OEM.DEFAULT,
 };
--- a/src/constants/defaultOptions.js
+++ b/src/constants/defaultOptions.js
@ -0,0 +1,13 @@
 module.exports = {
  /*
   * default path for downloading *.traineddata
   */
  langPath: 'https://tessdata.projectnaptha.com/4.0.0',
  /*
   * Use BlobURL for worker script by default
   * TODO: remove this option
   *
   */
  workerBlobURL: true,
  logger: () => {},
 };
--- a/src/common/createJob.js
+++ b/src/common/createJob.js
@ -1,4 +1,4 @@
-const { sendPacket } = require('../node');
+const { send } = require('./worker/node');
 let jobCounter = 0;
@ -11,7 +11,7 @@ module.exports = (
  const start = (worker) => {
    console.log(`[${worker.id}]: Start ${id}, action=${action}`);
-    sendPacket(worker, {
+    send(worker, {
      workerId: worker.id,
      jobId: id,
      action,
--- a/src/common/createScheduler.js
+++ b/src/common/createScheduler.js
--- a/src/common/createTesseract.js
+++ b/src/common/createTesseract.js
--- a/src/createWorker.js
+++ b/src/createWorker.js
@ -0,0 +1,100 @@
 const resolvePaths = require('./utils/resolvePaths');
 const circularize = require('./utils/circularize');
 const createJob = require('./createJob');
 const { defaultOEM } = require('./constants/config');
 const {
  defaultOptions,
  spawnWorker,
  terminateWorker,
  onMessage,
 } = require('./worker/node');
 let workerCounter = 0;
 module.exports = (_options = {}) => {
  workerCounter += 1;
  const id = `Worker-${workerCounter}-${Math.random().toString(16).slice(3, 8)}`;
  const options = resolvePaths({
    ...defaultOptions,
    ..._options,
  });
  const { logger } = options;
  const resolves = {};
  const rejects = {};
  let worker = spawnWorker(options);
  const setResolve = (action, res) => {
    resolves[action] = res;
  };
  const setReject = (action, rej) => {
    rejects[action] = rej;
  };
  const doJob = (action, payload) => (
    new Promise((resolve, reject) => {
      setResolve(action, resolve);
      setReject(action, reject);
      createJob(action, payload).start({ worker, id });
    })
  );
  const load = () => (
    doJob('load', { options })
  );
  const loadLanguage = (langs = 'eng') => (
    doJob('load-language', { langs, options })
  );
  const initialize = (langs = 'eng', oem = defaultOEM) => (
    doJob('initialize', { langs, oem })
  );
  const setParameters = (params = {}) => (
    doJob('set-parameters', { params })
  );
  const terminate = () => {
    if (worker !== null) {
      terminateWorker(worker);
      worker = null;
    }
  };
  onMessage(worker, (packet) => {
    const { status, action, data } = packet;
    if (status === 'resolve') {
      if (action === 'load') {
        resolves.load(data);
      } else if (action === 'initialize') {
        resolves.initialize({ id });
      } else if (action === 'set-parameters') {
        resolves['set-parameters'](data);
      } else if (action === 'load-language') {
        resolves['load-language'](data);
      } else if (action === 'recognize') {
        resolves.recognize(circularize(data));
      } else if (action === 'detect') {
        resolves.detect(data);
      }
    } else if (status === 'reject') {
      rejects[action](data);
      throw Error(data);
    } else if (status === 'progress') {
      logger(data);
    }
  });
  return {
    id,
    worker,
    setResolve,
    setReject,
    load,
    loadLanguage,
    initialize,
    setParameters,
    terminate,
  };
 };
--- a/src/index.js
+++ b/src/index.js
@ -7,20 +7,15 @@
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
-const utils = require('tesseract.js-utils');
+const createScheduler = require('./createScheduler');
-const TesseractWorker = require('./common/TesseractWorker');
+const createWorker = require('./createWorker');
-const createScheduler = require('./common/createScheduler');
+const createJob = require('./createJob');
-const createWorker = require('./common/createWorker');
+const OEM = require('./constants/OEM');
-const createJob = require('./common/createJob');
+const PSM = require('./constants/PSM');
 const types = require('./common/types');
 module.exports = {
-  /** Worker for OCR, @see common/TesseractWorker.js */
+  OEM,
-  TesseractWorker,
+  PSM,
  /** Utilities for tesseract.js, @see {@link https://www.npmjs.com/package/tesseract.js-utils} */
  utils,
  /** Check ./common/types for more details */
  ...types,
  createScheduler,
  createWorker,
  createJob,
--- a/src/node/b64toU8Array.js
+++ b/src/node/b64toU8Array.js
@ -1 +0,0 @@
 module.exports = s => Buffer.from(s, 'base64');
--- a/src/node/index.js
+++ b/src/node/index.js
@ -1,111 +0,0 @@
 /**
 *
 * Tesseract Worker adapter for node
 *
 * @fileoverview Tesseract Worker adapter for node
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 const util = require('util');
 const fs = require('fs');
 const axios = require('axios');
 const isURL = require('is-url');
 const { fork } = require('child_process');
 const path = require('path');
 const b64toU8Array = require('./b64toU8Array');
 const { defaultOptions } = require('../common/options');
 const readFile = util.promisify(fs.readFile);
 /**
 * loadImage
 *
 * @name loadImage
 * @function load image from different source
 * @access public
 * @param {string} image - image source, supported formats:
 *   string: URL string or file path
 *   string: base64 image
 *   buffer: image buffer
 * @returns {array} binary image in array format
 */
 const loadImage = (image) => {
  if (isURL(image)) {
    return axios.get(image, {
      responseType: 'arraybuffer',
    })
      .then(resp => resp.data);
  }
  if (/data:image\/([a-zA-Z]*);base64,([^"]*)/.test(image)) {
    return Promise.resolve(b64toU8Array(image.split(',')[1]));
  }
  if (Buffer.isBuffer(image)) {
    return Promise.resolve(image);
  }
  return readFile(image);
 };
 /*
 * Default options for node worker
 */
 exports.defaultOptions = {
  ...defaultOptions,
  workerPath: path.join(__dirname, 'worker.js'),
 };
 /**
 * spawnWorker
 *
 * @name spawnWorker
 * @function fork a new process in node
 * @access public
 * @param {object} instance - TesseractWorker instance
 * @param {object} options
 * @param {string} options.workerPath - worker script path
 */
 exports.spawnWorker = ({ workerPath }) => (
  fork(workerPath)
 );
 exports.setOnMessage = (worker, handler) => {
  worker.on('message', handler);
 };
 /**
 * terminateWorker
 *
 * @name terminateWorker
 * @function kill worker
 * @access public
 * @param {object} instance TesseractWorker instance
 */
 exports.terminateWorker = ({ worker }) => {
  worker.kill();
 };
 /**
 * sendPacket
 *
 * @name sendPacket
 * @function send packet to worker and create a job
 * @access public
 * @param {object} instance TesseractWorker instance
 * @param {object} iPacket data for worker
 */
 exports.sendPacket = ({ worker }, packet) => {
  const p = { ...packet };
  if (['recognize', 'detect'].includes(p.action)) {
    loadImage(p.payload.image)
      .then(buf => new Uint8Array(buf))
      .then((img) => {
        p.payload.image = Array.from(img);
        worker.send(p);
      });
  } else {
    worker.send(p);
  }
 };
--- a/src/node/worker.js
+++ b/src/node/worker.js
@ -1,44 +0,0 @@
 /**
 *
 * Node worker implementation
 *
 * @fileoverview Node worker implementation
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 const check = require('check-types');
 const workerUtils = require('../common/workerUtils');
 const b64toU8Array = require('./b64toU8Array');
 let TesseractCore = null;
 /*
 * register message handler
 */
 process.on('message', (packet) => {
  workerUtils.dispatchHandlers(packet, obj => process.send(obj));
 });
 /*
 * getCore is a sync function to load and return
 * TesseractCore.
 */
 workerUtils.setAdapter({
  getCore: (corePath, res) => {
    if (check.null(TesseractCore)) {
      res.progress({ status: 'loading tesseract core', progress: 0 });
      TesseractCore = require('tesseract.js-core');
      res.progress({ status: 'loaded tesseract core', progress: 1 });
    }
    return TesseractCore;
  },
  b64toU8Array,
  writeFile: (path, data) => {
    const fs = require('fs');
    fs.writeFile(path, data, (err) => {
      if (err) throw err;
    });
  },
 });
--- a/src/utils/circularize.js
+++ b/src/utils/circularize.js
@ -0,0 +1,57 @@
 /**
 * In the recognition result of tesseract, there
 * is a deep JSON object for details, it has around
 *
 * The result of dump.js is a big JSON tree
 * which can be easily serialized (for instance
 * to be sent from a webworker to the main app
 * or through Node's IPC), but we want
 * a (circular) DOM-like interface for walking
 * through the data.
 *
 * A (circular) DOM-like interface here means that
 * each child element
 *
 * @fileoverview DOM-like interface for walking through data
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 module.exports = (page) => {
  const blocks = [];
  const paragraphs = [];
  const lines = [];
  const words = [];
  const symbols = [];
  page.blocks.forEach((block) => {
    block.paragraphs.forEach((paragraph) => {
      paragraph.lines.forEach((line) => {
        line.words.forEach((word) => {
          word.symbols.forEach((sym) => {
            symbols.push({
              ...sym, page, block, paragraph, line, word,
            });
          });
          words.push({
            ...word, page, block, paragraph, line,
          });
        });
        lines.push({
          ...line, page, block, paragraph,
        });
      });
      paragraphs.push({
        ...paragraph, page, block,
      });
    });
    blocks.push({
      ...block, page,
    });
  });
  return {
    ...page, blocks, paragraphs, lines, words, symbols,
  };
 };
--- a/src/utils/getEnvironment.js
+++ b/src/utils/getEnvironment.js
@ -0,0 +1,10 @@
 module.exports = (key) => {
  const env = {
    type: (typeof window !== 'undefined') && (typeof window.document !== 'undefined') ? 'browser' : 'node',
  };
  if (typeof key === 'undefined') {
    return env;
  }
  return env[key];
 };
--- a/src/utils/resolvePaths.js
+++ b/src/utils/resolvePaths.js
@ -0,0 +1,12 @@
 const isBrowser = require('./getEnvironment')('type') === 'browser';
 const resolveURL = isBrowser ? require('resolve-url') : s => s; // eslint-disable-line
 module.exports = (options) => {
  const opts = { ...options };
  ['corePath', 'workerPath', 'langPath'].forEach((key) => {
    if (typeof options[key] !== 'undefined') {
      opts[key] = resolveURL(opts[key]);
    }
  });
  return opts;
 };
--- a/src/worker-script/browser/index.js
+++ b/src/worker-script/browser/index.js
--- a/src/worker-script/constants/defaultParams.js
+++ b/src/worker-script/constants/defaultParams.js
@ -0,0 +1,24 @@
 /*
 * default params for tesseract.js
 */
 const PSM = require('../../constants/PSM');
 module.exports = {
  tessedit_pageseg_mode: PSM.SINGLE_BLOCK,
  tessedit_char_whiltelist: '',
  tessjs_create_pdf: '0',
  tessjs_create_hocr: '1',
  tessjs_create_tsv: '1',
  tessjs_create_box: '0',
  tessjs_create_unlv: '0',
  tessjs_create_osd: '0',
  tessjs_textonly_pdf: '0',
  tessjs_pdf_name: 'tesseract.js-ocr-result',
  tessjs_pdf_title: 'Tesseract.js OCR Result',
  tessjs_pdf_auto_download: true,
  tessjs_pdf_bin: false,
  tessjs_image_rectangle_left: 0,
  tessjs_image_rectangle_top: 0,
  tessjs_image_rectangle_width: -1,
  tessjs_image_rectangle_height: -1,
 };
--- a/src/worker-script/index.js
+++ b/src/worker-script/index.js
@ -1,18 +1,18 @@
 /**
 *
- * Worker utilities for browser and node
+ * Worker script for browser and node
 *
- * @fileoverview Worker utilities for browser and node
+ * @fileoverview Worker script for browser and node
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 const { loadLang } = require('tesseract.js-utils');
-const pdfTTF = require('./pdf-ttf');
+const dump = require('./utils/dump');
-const dump = require('./dump');
+const isBrowser = require('../utils/getEnvironment')('type') === 'browser';
-const { OEM, PSM } = require('./types');
+const setImage = require('./utils/setImage');
-const { isBrowser } = require('./env');
+const getFiles = require('./utils/getFiles');
-const { setImage, getLangsStr, getFiles } = require('./utils');
+const defaultParams = require('./constants/defaultParams');
 /*
 * Tesseract Module returned by TesseractCore.
@ -24,7 +24,7 @@ let TessModule;
 let api;
 let latestJob;
 let adapter = {};
-let curParams = {};
+let params = defaultParams;
 /**
@ -38,7 +38,7 @@ let curParams = {};
 * @param {object} res - job instance
 * @returns {Promise} A Promise for callback
 */
-const load = ({ workerId, jobId, payload: { corePath } }, res) => {
+const load = ({ workerId, jobId, payload: { options: { corePath } } }, res) => {
  if (!TessModule) {
    const Core = adapter.getCore(corePath, res);
@ -56,8 +56,6 @@ const load = ({ workerId, jobId, payload: { corePath } }, res) => {
    })
      .then((tessModule) => {
        TessModule = tessModule;
        TessModule.FS.writeFile('/pdf.ttf', adapter.b64toU8Array(pdfTTF));
        api = new TessModule.TessBaseAPI();
        res.progress({ workerId, status: 'initialized tesseract', progress: 1 });
        res.resolve({ loaded: true });
      });
@ -83,52 +81,55 @@ const loadLanguage = ({ workerId, payload: { langs, options } }, res) => {
  loadLang({ langs, TessModule, ...options }).then(() => {
    res.progress({ workerId, status: 'loaded language traineddata', progress: 1 });
    res.resolve(langs);
-  }).catch((e) => {
+  }).catch((err) => {
-    if (isBrowser && e instanceof DOMException) {
+    if (isBrowser && err instanceof DOMException) {
      /*
       * For some reason google chrome throw DOMException in loadLang,
       * while other browser is OK, for now we ignore this exception
       * and hopefully to find the root cause one day.
       */
    } else {
-      res.reject(e.toString());
+      res.reject(err.toString());
    }
  });
 };
 const setParameters = ({ payload: { params: _params } }, res) => {
  Object.keys(_params)
    .filter(k => !k.startsWith('tessjs_'))
    .forEach((key) => {
      api.SetVariable(key, _params[key]);
    });
  params = { ...params, ..._params };
  if (typeof res !== 'undefined') {
    res.resolve(params);
  }
 };
 const initialize = ({
  workerId,
  jobId,
-  payload: { langs, params },
+  payload: { langs: _langs, oem },
 }, res) => {
-  let { tessedit_ocr_engine_mode: oem } = params;
+  const langs = (typeof _langs === 'string')
-  let l = langs;
+    ? _langs
    : _langs.map(l => ((typeof l === 'string') ? l : l.data)).join('+');
-  res.progress({
+  try {
-    workerId, jobId, status: 'initializing api', progress: 0,
+    res.progress({
-  });
+      workerId, jobId, status: 'initializing api', progress: 0,
-  if ([
+    });
-    PSM.OSD_ONLY,
+    api = new TessModule.TessBaseAPI();
-    PSM.AUTO_OSD,
+    api.Init(null, langs, oem);
-    PSM.RAW_LINE,
+    setParameters({ payload: { params } });
-  ].includes(params.tessedit_pageseg_mode)) {
+    res.progress({
-    l = (typeof l === 'string') ? `${l}+osd` : [...l, 'osd'];
+      workerId, jobId, status: 'initialized api', progress: 1,
-    // oem = OEM.TESSERACT_ONLY;
+    });
    res.resolve();
  } catch (err) {
    res.reject(err.toString());
  }
  api.Init(null, getLangsStr(l), oem);
  Object.keys(params).forEach((key) => {
    if (!key.startsWith('tessjs')) {
      api.SetVariable(key, params[key]);
    }
  });
  curParams = {
    tessedit_ocr_engine_mode: oem,
    ...params,
  };
  res.progress({
    workerId, jobId, status: 'initialized api', progress: 1,
  });
  res.resolve();
 };
 /**
@ -146,11 +147,11 @@ const initialize = ({
 */
 const recognize = ({ payload: { image } }, res) => {
  try {
-    const ptr = setImage(TessModule, api, image, curParams);
+    const ptr = setImage(TessModule, api, image, params);
    api.Recognize(null);
    res.resolve({
-      files: getFiles(TessModule, api, adapter, curParams),
+      files: getFiles(TessModule, api, adapter, params),
-      ...dump(TessModule, api, curParams),
+      ...dump(TessModule, api, params),
    });
    TessModule._free(ptr);
  } catch (err) {
@ -172,7 +173,7 @@ const recognize = ({ payload: { image } }, res) => {
 */
 const detect = ({ payload: { image } }, res) => {
  try {
-    const ptr = setImage(TessModule, api, image, curParams);
+    const ptr = setImage(TessModule, api, image, params);
    const results = new TessModule.OSResults();
    if (!api.DetectOS(results)) {
@ -199,6 +200,15 @@ const detect = ({ payload: { image } }, res) => {
  }
 };
 const terminate = (_, res) => {
  try {
    api.End();
    res.resolve({ terminated: true });
  } catch (err) {
    res.reject(err.toString());
  }
 };
 /**
 * dispatchHandlers
 *
@ -233,10 +243,14 @@ exports.dispatchHandlers = (packet, send) => {
      loadLanguage(packet, res);
    } else if (action === 'initialize') {
      initialize(packet, res);
    } else if (action === 'set-parameters') {
      setParameters(packet, res);
    } else if (action === 'recognize') {
      recognize(packet, res);
    } else if (action === 'detect') {
      detect(packet, res);
    } else if (action === 'terminate') {
      terminate(packet, res);
    }
  } catch (err) {
    /** Prepare exception to travel through postMessage */
@ -250,8 +264,8 @@ exports.dispatchHandlers = (packet, send) => {
 * @name setAdapter
 * @function
 * @access public
- * @param {object} impl - implementation of the worker, different in browser and node environment
+ * @param {object} adapter - implementation of the worker, different in browser and node environment
 */
-exports.setAdapter = (impl) => {
+exports.setAdapter = (_adapter) => {
-  adapter = impl;
+  adapter = _adapter;
 };
--- a/src/worker-script/node/exportFile.js
+++ b/src/worker-script/node/exportFile.js
@ -0,0 +1,7 @@
 const fs = require('fs');
 module.exports = (path, data) => {
  fs.writeFile(path, data, (err) => {
    if (err) throw err;
  });
 };
--- a/src/worker-script/node/index.js
+++ b/src/worker-script/node/index.js
@ -0,0 +1,39 @@
 /**
 *
 * Tesseract Worker Script for Node
 *
 * @fileoverview Node worker implementation
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 const worker = require('../');
 const exportFile = require('./exportFile');
 let TesseractCore = null;
 /*
 * register message handler
 */
 process.on('message', (packet) => {
  worker.dispatchHandlers(packet, obj => process.send(obj));
 });
 /*
 * getCore is a sync function to load and return
 * TesseractCore.
 */
 const getCore = (_, res) => {
  if (TesseractCore === null) {
    res.progress({ status: 'loading tesseract core', progress: 0 });
    TesseractCore = require('tesseract.js-core');
    res.progress({ status: 'loaded tesseract core', progress: 1 });
  }
  return TesseractCore;
 };
 worker.setAdapter({
  getCore,
  exportFile,
 });
--- a/src/worker-script/utils/dump.js
+++ b/src/worker-script/utils/dump.js
@ -50,6 +50,13 @@ module.exports = (TessModule, api, {
  tessjs_create_osd,
 }) => {
  const ri = api.GetIterator();
  const {
    RIL_BLOCK,
    RIL_PARA,
    RIL_TEXTLINE,
    RIL_WORD,
    RIL_SYMBOL,
  } = TessModule;
  const blocks = [];
  let block;
  let para;
@ -59,14 +66,13 @@ module.exports = (TessModule, api, {
  const enumToString = (value, prefix) => (
    Object.keys(TessModule)
-      .filter(e => (e.substr(0, prefix.length + 1) === `${prefix}_`))
+      .filter(e => (e.startsWith(`${prefix}_`) && TessModule[e] === value))
      .filter(e => TessModule[e] === value)
      .map(e => e.slice(prefix.length + 1))[0]
  );
  ri.Begin();
  do {
-    if (ri.IsAtBeginningOf(TessModule.RIL_BLOCK)) {
+    if (ri.IsAtBeginningOf(RIL_BLOCK)) {
      const poly = ri.BlockPolygon();
      let polygon = null;
      // BlockPolygon() returns null when automatic page segmentation is off
@ -86,47 +92,47 @@ module.exports = (TessModule, api, {
      block = {
        paragraphs: [],
-        text: ri.GetUTF8Text(TessModule.RIL_BLOCK),
+        text: ri.GetUTF8Text(RIL_BLOCK),
-        confidence: ri.Confidence(TessModule.RIL_BLOCK),
+        confidence: ri.Confidence(RIL_BLOCK),
-        baseline: ri.getBaseline(TessModule.RIL_BLOCK),
+        baseline: ri.getBaseline(RIL_BLOCK),
-        bbox: ri.getBoundingBox(TessModule.RIL_BLOCK),
+        bbox: ri.getBoundingBox(RIL_BLOCK),
        blocktype: enumToString(ri.BlockType(), 'PT'),
        polygon,
      };
      blocks.push(block);
    }
-    if (ri.IsAtBeginningOf(TessModule.RIL_PARA)) {
+    if (ri.IsAtBeginningOf(RIL_PARA)) {
      para = {
        lines: [],
-        text: ri.GetUTF8Text(TessModule.RIL_PARA),
+        text: ri.GetUTF8Text(RIL_PARA),
-        confidence: ri.Confidence(TessModule.RIL_PARA),
+        confidence: ri.Confidence(RIL_PARA),
-        baseline: ri.getBaseline(TessModule.RIL_PARA),
+        baseline: ri.getBaseline(RIL_PARA),
-        bbox: ri.getBoundingBox(TessModule.RIL_PARA),
+        bbox: ri.getBoundingBox(RIL_PARA),
        is_ltr: !!ri.ParagraphIsLtr(),
      };
      block.paragraphs.push(para);
    }
-    if (ri.IsAtBeginningOf(TessModule.RIL_TEXTLINE)) {
+    if (ri.IsAtBeginningOf(RIL_TEXTLINE)) {
      textline = {
        words: [],
-        text: ri.GetUTF8Text(TessModule.RIL_TEXTLINE),
+        text: ri.GetUTF8Text(RIL_TEXTLINE),
-        confidence: ri.Confidence(TessModule.RIL_TEXTLINE),
+        confidence: ri.Confidence(RIL_TEXTLINE),
-        baseline: ri.getBaseline(TessModule.RIL_TEXTLINE),
+        baseline: ri.getBaseline(RIL_TEXTLINE),
-        bbox: ri.getBoundingBox(TessModule.RIL_TEXTLINE),
+        bbox: ri.getBoundingBox(RIL_TEXTLINE),
      };
      para.lines.push(textline);
    }
-    if (ri.IsAtBeginningOf(TessModule.RIL_WORD)) {
+    if (ri.IsAtBeginningOf(RIL_WORD)) {
      const fontInfo = ri.getWordFontAttributes();
      const wordDir = ri.WordDirection();
      word = {
        symbols: [],
        choices: [],
-        text: ri.GetUTF8Text(TessModule.RIL_WORD),
+        text: ri.GetUTF8Text(RIL_WORD),
-        confidence: ri.Confidence(TessModule.RIL_WORD),
+        confidence: ri.Confidence(RIL_WORD),
-        baseline: ri.getBaseline(TessModule.RIL_WORD),
+        baseline: ri.getBaseline(RIL_WORD),
-        bbox: ri.getBoundingBox(TessModule.RIL_WORD),
+        bbox: ri.getBoundingBox(RIL_WORD),
        is_numeric: !!ri.WordIsNumeric(),
        in_dictionary: !!ri.WordIsFromDictionary(),
@ -159,14 +165,14 @@ module.exports = (TessModule, api, {
    // var image = pix2array(pix);
    // // for some reason it seems that things stop working if you destroy pics
    // TessModule._pixDestroy(TessModule.getPointer(pix));
-    if (ri.IsAtBeginningOf(TessModule.RIL_SYMBOL)) {
+    if (ri.IsAtBeginningOf(RIL_SYMBOL)) {
      symbol = {
        choices: [],
        image: null,
-        text: ri.GetUTF8Text(TessModule.RIL_SYMBOL),
+        text: ri.GetUTF8Text(RIL_SYMBOL),
-        confidence: ri.Confidence(TessModule.RIL_SYMBOL),
+        confidence: ri.Confidence(RIL_SYMBOL),
-        baseline: ri.getBaseline(TessModule.RIL_SYMBOL),
+        baseline: ri.getBaseline(RIL_SYMBOL),
-        bbox: ri.getBoundingBox(TessModule.RIL_SYMBOL),
+        bbox: ri.getBoundingBox(RIL_SYMBOL),
        is_superscript: !!ri.SymbolIsSuperscript(),
        is_subscript: !!ri.SymbolIsSubscript(),
        is_dropcap: !!ri.SymbolIsDropcap(),
@ -181,7 +187,7 @@ module.exports = (TessModule, api, {
      } while (ci.Next());
      // TessModule.destroy(i);
    }
-  } while (ri.Next(TessModule.RIL_SYMBOL));
+  } while (ri.Next(RIL_SYMBOL));
  TessModule.destroy(ri);
  return {
--- a/src/worker-script/utils/getFiles.js
+++ b/src/worker-script/utils/getFiles.js
@ -0,0 +1,39 @@
 /**
 * handleOutput
 *
 * @name handleOutput
 * @function handle file output
 * @access private
 * @param {object} customParams - an object of params
 */
 module.exports = (TessModule, api, adapter, params) => {
  let files = {};
  const {
    tessjs_create_pdf,
    tessjs_textonly_pdf,
    tessjs_pdf_name,
    tessjs_pdf_title,
    tessjs_pdf_auto_download,
    tessjs_pdf_bin,
  } = params;
  if (tessjs_create_pdf === '1') {
    const pdfRenderer = new TessModule.TessPDFRenderer(tessjs_pdf_name, '/', tessjs_textonly_pdf === '1');
    pdfRenderer.BeginDocument(tessjs_pdf_title);
    pdfRenderer.AddImage(api);
    pdfRenderer.EndDocument();
    TessModule._free(pdfRenderer);
    const data = TessModule.FS.readFile(`/${tessjs_pdf_name}.pdf`);
    if (tessjs_pdf_bin) {
      files = { pdf: data, ...files };
    }
    if (tessjs_pdf_auto_download) {
      adapter.exportFile(`${tessjs_pdf_name}.pdf`, data, 'application/pdf');
    }
  }
  return files;
 };
--- a/src/worker-script/utils/getLangStr.js
+++ b/src/worker-script/utils/getLangStr.js
@ -0,0 +1,5 @@
 module.exports = langs => (
  typeof langs === 'string'
    ? langs
    : langs.map(lang => (typeof lang === 'string' ? lang : lang.data)).join('+')
 );
--- a/src/worker-script/utils/setImage.js
+++ b/src/worker-script/utils/setImage.js
@ -0,0 +1,41 @@
 const { readImage } = require('tesseract.js-utils');
 /**
 * setImage
 *
 * @name setImage
 * @function set image in tesseract for recognition
 * @access public
 * @param {array} image - binary array in array format
 * @returns {number} - an emscripten pointer of the image
 */
 module.exports = (TessModule, api, image, params) => {
  const {
    tessjs_image_rectangle_left: left,
    tessjs_image_rectangle_top: top,
    tessjs_image_rectangle_width: width,
    tessjs_image_rectangle_height: height,
  } = params;
  const {
    w, h, bytesPerPixel, data, pix,
  } = readImage(TessModule, Array.from(image));
  /*
   * As some image format (ex. bmp) is not supported natiely by tesseract,
   * sometimes it will not return pix directly, but data and bytesPerPixel
   * for another SetImage usage.
   *
   */
  if (data === null) {
    api.SetImage(pix);
  } else {
    api.SetImage(data, w, h, bytesPerPixel, w * bytesPerPixel);
  }
  api.SetRectangle(
    (left < 0) ? 0 : left,
    (top < 0) ? 0 : top,
    (width < 0) ? w : width,
    (height < 0) ? h : height,
  );
  return data === null ? pix : data;
 };
--- a/src/worker/browser/b64toU8Array.js
+++ b/src/worker/browser/b64toU8Array.js
--- a/src/worker/browser/index.js
+++ b/src/worker/browser/index.js
--- a/src/worker/browser/worker.js
+++ b/src/worker/browser/worker.js
@ -1,6 +1,6 @@
 /**
 *
- * Browser worker implementation
+ * Browser worker scripts
 *
 * @fileoverview Browser worker implementation
 * @author Kevin Kwok <antimatter15@gmail.com>
@ -9,21 +9,21 @@
 */
 const check = require('check-types');
-const workerUtils = require('../common/workerUtils');
+const workerWrapper = require('../../workerWrapper');
 const b64toU8Array = require('./b64toU8Array');
 /*
 * register message handler
 */
 global.addEventListener('message', ({ data }) => {
-  workerUtils.dispatchHandlers(data, obj => postMessage(obj));
+  workerWrapper.dispatchHandlers(data, obj => postMessage(obj));
 });
 /*
 * getCore is a sync function to load and return
 * TesseractCore.
 */
-workerUtils.setAdapter({
+workerWrapper.setAdapter({
  getCore: (corePath, res) => {
    if (check.undefined(global.TesseractCore)) {
      res.progress({ status: 'loading tesseract core', progress: 0 });
--- a/src/worker/node/defaultOptions.js
+++ b/src/worker/node/defaultOptions.js
@ -0,0 +1,10 @@
 const path = require('path');
 const defaultOptions = require('../../constants/defaultOptions');
 /*
 * Default options for node worker
 */
 module.exports = {
  ...defaultOptions,
  workerPath: path.join(__dirname, '..', '..', 'worker-script', 'node', 'index.js'),
 };
--- a/src/worker/node/index.js
+++ b/src/worker/node/index.js
@ -0,0 +1,22 @@
 /**
 *
 * Tesseract Worker impl. for node (using child_process)
 *
 * @fileoverview Tesseract Worker impl. for node
 * @author Kevin Kwok <antimatter15@gmail.com>
 * @author Guillermo Webster <gui@mit.edu>
 * @author Jerome Wu <jeromewus@gmail.com>
 */
 const defaultOptions = require('./defaultOptions');
 const spawnWorker = require('./spawnWorker');
 const terminateWorker = require('./terminateWorker');
 const onMessage = require('./onMessage');
 const send = require('./send');
 module.exports = {
  defaultOptions,
  spawnWorker,
  terminateWorker,
  onMessage,
  send,
 };
--- a/src/worker/node/onMessage.js
+++ b/src/worker/node/onMessage.js
@ -0,0 +1,3 @@
 module.exports = (worker, handler) => {
  worker.on('message', handler);
 };
--- a/src/worker/node/send.js
+++ b/src/worker/node/send.js
@ -0,0 +1,61 @@
 const util = require('util');
 const fs = require('fs');
 const axios = require('axios');
 const isURL = require('is-url');
 const readFile = util.promisify(fs.readFile);
 /**
 * loadImage
 *
 * @name loadImage
 * @function load image from different source
 * @access public
 * @param {string} image - image source, supported formats:
 *   string: URL string or file path
 *   string: base64 image
 *   buffer: image buffer
 * @returns {array} binary image in array format
 */
 const loadImage = (image) => {
  if (isURL(image)) {
    return axios.get(image, {
      responseType: 'arraybuffer',
    })
      .then(resp => resp.data);
  }
  if (/data:image\/([a-zA-Z]*);base64,([^"]*)/.test(image)) {
    return Promise.resolve(Buffer.from(image.split(',')[1], 'base64'));
  }
  if (Buffer.isBuffer(image)) {
    return Promise.resolve(image);
  }
  return readFile(image);
 };
 /**
 * send
 *
 * @name send
 * @function send packet to worker and create a job
 * @access public
 * @param {object} instance TesseractWorker instance
 * @param {object} iPacket data for worker
 */
 module.exports = ({ worker }, packet) => {
  const p = { ...packet };
  if (['recognize', 'detect'].includes(p.action)) {
    loadImage(p.payload.image)
      .then(buf => new Uint8Array(buf))
      .then((img) => {
        p.payload.image = Array.from(img);
        worker.send(p);
      });
  } else {
    worker.send(p);
  }
 };
--- a/src/worker/node/spawnWorker.js
+++ b/src/worker/node/spawnWorker.js
@ -0,0 +1,15 @@
 const { fork } = require('child_process');
 /**
 * spawnWorker
 *
 * @name spawnWorker
 * @function fork a new process in node
 * @access public
 * @param {object} instance - TesseractWorker instance
 * @param {object} options
 * @param {string} options.workerPath - worker script path
 */
 module.exports = ({ workerPath }) => (
  fork(workerPath)
 );
--- a/src/worker/node/terminateWorker.js
+++ b/src/worker/node/terminateWorker.js
@ -0,0 +1,11 @@
 /**
 * terminateWorker
 *
 * @name terminateWorker
 * @function kill worker
 * @access public
 * @param {object} instance TesseractWorker instance
 */
 module.exports = (worker) => {
  worker.kill();
 };
		`@ -1 +0,0 @@`
			`exports.isBrowser = (typeof window !== 'undefined') && (typeof window.document !== 'undefined');`
		`@ -1 +0,0 @@`
			module.exports = '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';
		`@ -1 +0,0 @@`
			`module.exports = s => Buffer.from(s, 'base64');`