Updated createWorker to be async

src/createWorker.js

@@ -15,7 +15,7 @@ const {
 
 let workerCounter = 0;
 
-module.exports = (_options = {}) => {
+module.exports = async (_options = {}) => {
   const id = getId('Worker', workerCounter);
   const {
     logger,
@@ -27,7 +27,18 @@ module.exports = (_options = {}) => {
   });
   const resolves = {};
   const rejects = {};
+
+  let resReject;
+  let resResolve; 
+  const res = new Promise((resolve, reject) => {
+    resResolve = resolve;
+    resReject = reject;
+  });
+  let workerError = (event) => {resReject(event.message)};
+  
   let worker = spawnWorker(options);
+  // worker.addEventListener("error", workerError);
+  worker.onerror = workerError;
 
   workerCounter += 1;
 
@@ -185,7 +196,7 @@ module.exports = (_options = {}) => {
     }
   });
 
-  return {
+  const resolveObj = {
     id,
     worker,
     setResolve,
@@ -204,4 +215,14 @@ module.exports = (_options = {}) => {
     detect,
     terminate,
   };
+
+  startJob(createJob({
+    id: undefined, action: 'checkWorker',
+  })).then(() => {
+    console.log("Created worker");
+    // worker.removeEventListener("error", workerError);
+    resResolve(resolveObj)});
+
+  return res;
+
 };

src/worker-script/index.js

@@ -57,7 +57,7 @@ const load = async ({ workerId, jobId, payload: { options: { corePath, logging }
   }
 };
 
-const FS = ({ workerId, payload: { method, args } }, res) => {
+const FS = async ({ workerId, payload: { method, args } }, res) => {
   log(`[${workerId}]: FS.${method} with args ${args}`);
   res.resolve(TessModule.FS[method](...args));
 };
@@ -159,7 +159,7 @@ res) => {
   }
 };
 
-const setParameters = ({ payload: { params: _params } }, res) => {
+const setParameters = async ({ payload: { params: _params } }, res) => {
   Object.keys(_params)
     .filter((k) => !k.startsWith('tessjs_'))
     .forEach((key) => {
@@ -172,7 +172,7 @@ const setParameters = ({ payload: { params: _params } }, res) => {
   }
 };
 
-const initialize = ({
+const initialize = async ({
   workerId,
   payload: { langs: _langs, oem },
 }, res) => {
@@ -208,7 +208,7 @@ const getImage = (type) => {
   return pngStr;
 };
 
-const recognize = ({
+const recognize = async ({
   payload: {
     image, options: {
       rectangle: rec, saveImageOriginal, saveImageGrey, saveImageBinary, rotateAuto, rotateRadians,
@@ -280,7 +280,7 @@ const recognize = ({
 
 // `threshold` is similar to `recognize` except it skips the recognition step
 // Useful for getting rotated/binarized images without running recognition
-const threshold = ({
+const threshold = async ({
   payload: {
     image, options: {
       rectangle: rec, saveImageOriginal, saveImageGrey, saveImageBinary, rotateAuto, rotateRadians,
@@ -340,7 +340,7 @@ const threshold = ({
   }
 };
 
-const getPDF = ({ payload: { title, textonly } }, res) => {
+const getPDF = async ({ payload: { title, textonly } }, res) => {
   const pdfRenderer = new TessModule.TessPDFRenderer('tesseract-ocr', '/', textonly);
   pdfRenderer.BeginDocument(title);
   pdfRenderer.AddImage(api);
@@ -350,7 +350,7 @@ const getPDF = ({ payload: { title, textonly } }, res) => {
   res.resolve(TessModule.FS.readFile('/tesseract-ocr.pdf'));
 };
 
-const detect = ({ payload: { image } }, res) => {
+const detect = async ({ payload: { image } }, res) => {
   try {
     const ptr = setImage(TessModule, api, image);
     const results = new TessModule.OSResults();
@@ -379,7 +379,7 @@ const detect = ({ payload: { image } }, res) => {
   }
 };
 
-const terminate = (_, res) => {
+const terminate = async (_, res) => {
   try {
     if (api !== null) {
       api.End();
@@ -390,6 +390,13 @@ const terminate = (_, res) => {
   }
 };
 
+// Function that always resolves
+// Used to confirm that worker was successfully created
+const checkWorker = async (_, res) => {
+  res.resolve();
+};
+
+
 /**
  * dispatchHandlers
  *
@@ -416,7 +423,6 @@ exports.dispatchHandlers = (packet, send) => {
 
   latestJob = res;
 
-  try {
     ({
       load,
       FS,
@@ -428,11 +434,9 @@ exports.dispatchHandlers = (packet, send) => {
       getPDF,
       detect,
       terminate,
-    })[packet.action](packet, res);
+      checkWorker
-  } catch (err) {
+    })[packet.action](packet, res)
-    /** Prepare exception to travel through postMessage */
+    .catch((err) => res.reject(err.toString()));
-    res.reject(err.toString());
-  }
 };
 
 /**

tests/FS.test.js

@@ -1,8 +1,9 @@
 const { createWorker } = Tesseract;
 const FS_WAIT = 500;
-const worker = createWorker(OPTIONS);
+let worker;
-before(function cb() {
+before(async function cb() {
   this.timeout(0);
+  worker = await createWorker(OPTIONS);
   return worker.load();
 });
 

tests/detect.test.js

@@ -1,7 +1,8 @@
 const { createWorker } = Tesseract;
-const worker = createWorker(OPTIONS);
+let worker;
-before(function cb() {
+before(async function cb() {
   this.timeout(0);
+  worker = await createWorker(OPTIONS);
   return worker.load();
 });
 

tests/error.test.html

@@ -0,0 +1,18 @@
+<html>
+  <head>
+    <meta charset="utf-8">
+    <link rel="stylesheet" href="../node_modules/mocha/mocha.css">
+  </head>
+  <body>
+    <div id="mocha"></div>
+    <script src="../node_modules/mocha/mocha.js"></script>
+    <script src="../node_modules/expect.js/index.js"></script>
+    <script src="../dist/tesseract.dev.js"></script>
+    <script src="./constants.js"></script>
+    <script>mocha.setup('bdd');</script>
+    <script src="./error.test.js"></script>
+    <script>
+      mocha.run();
+    </script>
+  </body>
+</html>

tests/error.test.js

@@ -0,0 +1,29 @@
+// const { createWorker } = Tesseract;
+// const worker = createWorker(OPTIONS);
+// before(function cb() {
+//   this.timeout(0);
+//   return worker.load();
+// });
+
+
+(IS_BROWSER ? describe : describe.skip)('Invalid paths should result in promise rejection', () => {
+    it('Invalid workerPath', async () => {
+    const OPTIONS1 = JSON.parse(JSON.stringify(OPTIONS));
+    OPTIONS1.corePath = "badpath.js";
+    let errorThrown;
+    try {
+      const worker = Tesseract.createWorker(OPTIONS1);
+      await worker.load()
+      errorThrown = false;
+    } catch (error) {
+      errorThrown = true;
+    }
+
+    expect(errorThrown).to.equal(true);
+
+    // expect(func).to.throwError();
+
+    // const ret = await (worker.load().then(() => true).catch(() => false));
+    // expect(ret).to.equal(false);
+    }).timeout(TIMEOUT);
+});

tests/recognize.test.js

@@ -1,7 +1,8 @@
 const { createWorker, PSM } = Tesseract;
-const worker = createWorker(OPTIONS);
+let worker;
 before(async function cb() {
   this.timeout(0);
+  worker = await createWorker(OPTIONS);
   await worker.load();
   await worker.loadLanguage('eng+chi_tra+osd');
 });

tests/scheduler.test.js

@@ -7,7 +7,7 @@ before(async function cb() {
   const NUM_WORKERS = 5;
   console.log(`Initializing ${NUM_WORKERS} workers`);
   workers = await Promise.all(Array(NUM_WORKERS).fill(0).map(async () => {
-    const w = createWorker(OPTIONS);
+    const w = await createWorker(OPTIONS);
     await w.load();
     await w.loadLanguage('eng');
     await w.initialize('eng');