decodeSingle: run all calls on a new Quagga instance

- this appears to actually work correctly, all tests are passing
- move stop functionality into the instance
- init accepts an instance parameter to determine which instance to init
- update bound to instance
- add Quagga::setReaders and Quagga::registerReader
- setupInputStream defaults to LiveStream per the TypeScript def for
  inputStream config
- InputStreamType back to optional in input stream config

src/quagga.js

@@ -15,32 +15,27 @@ const instance = new Quagga();
 const _context = instance.context;
 
 export default {
-    init: function (config, cb, imageWrapper) {
-        _context.config = merge({}, Config, config);
+    init: function (config, cb, imageWrapper, quaggaInstance = instance) {
+        quaggaInstance.context.config = merge({}, Config, config);
         // TODO: pending restructure in Issue #105, we are temp disabling workers
-        if (_context.config.numOfWorkers > 0) {
-            _context.config.numOfWorkers = 0;
+        if (quaggaInstance.context.config.numOfWorkers > 0) {
+            quaggaInstance.context.config.numOfWorkers = 0;
         }
         if (imageWrapper) {
-            _context.onUIThread = false;
-            instance.initializeData(imageWrapper);
+            quaggaInstance.context.onUIThread = false;
+            quaggaInstance.initializeData(imageWrapper);
             if (cb) {
                 cb();
             }
         } else {
-            instance.initInputStream(cb);
+            quaggaInstance.initInputStream(cb);
         }
     },
     start: function () {
         instance.start();
     },
     stop: function () {
-        _context.stopped = true;
-        QWorkers.adjustWorkerPool(0);
-        if (_context.config.inputStream && _context.config.inputStream.type === 'LiveStream') {
-            CameraAccess.release();
-            _context.inputStream.clearEventHandlers();
-        }
+        instance.stop();
     },
     pause: function () {
         _context.stopped = true;
@@ -70,6 +65,7 @@ export default {
     },
     canvas: _context.canvasContainer,
     decodeSingle: function (config, resultCallback) {
+        const quaggaInstance = new Quagga();
         if (this.inDecodeSingle) {
             // force multiple calls to decodeSingle to run in serial, because presently
             // simultaneous running breaks things.
@@ -84,7 +80,7 @@ export default {
             }
             return null;
         }
-        this.inDecodeSingle = true;
+        // this.inDecodeSingle = true;
         config = merge({
             inputStream: {
                 type: 'ImageStream',
@@ -113,14 +109,14 @@ export default {
                 this.init(config, () => {
                     Events.once('processed', (result) => {
                         this.inDecodeSingle = false;
-                        this.stop();
+                        quaggaInstance.stop();
                         if (resultCallback) {
                             resultCallback.call(null, result);
                         }
                         resolve(result);
                     }, true);
-                    instance.start();
-                });
+                    quaggaInstance.start();
+                }, null, quaggaInstance);
             } catch (err) {
                 this.inDecodeSingle = false;
                 reject(err);

src/quagga/quagga.ts

@@ -13,7 +13,7 @@ import CameraAccess from '../input/camera_access';
 import { clone } from 'gl-vec2';
 import { BarcodeInfo } from '../reader/barcode_reader';
 import { moveLine, moveBox } from './transform';
-import { QuaggaJSResultObject } from '../../type-definitions/quagga';
+import { QuaggaJSResultObject, QuaggaJSReaderConfig } from '../../type-definitions/quagga';
 import Events from '../common/events';
 
 const InputStream = typeof window === 'undefined' ? NodeInputStream : BrowserInputStream;
@@ -195,7 +195,7 @@ export default class Quagga {
         }
     }
 
-    update() {
+    update = () => {
         if (this.context.onUIThread) {
             const workersUpdated = QWorkers.updateWorkers(this.context.framegrabber);
             if (!workersUpdated) {
@@ -241,4 +241,27 @@ export default class Quagga {
         }
     }
 
+    stop() {
+        this.context.stopped = true;
+        QWorkers.adjustWorkerPool(0);
+        if (this.context.config?.inputStream && this.context.config.inputStream.type === 'LiveStream') {
+            CameraAccess.release();
+            this.context.inputStream.clearEventHandlers();
+        }
+    }
+
+    setReaders(readers: Array<QuaggaJSReaderConfig>) {
+        if (this.context.decoder) {
+            this.context.decoder.setReaders(readers);
+        }
+        QWorkers.setReaders(readers);
+    }
+
+    registerReader(name: string, reader: QuaggaJSReaderConfig) {
+        BarcodeDecoder.registerReader(name, reader);
+        if (this.context.decoder) {
+            this.context.decoder.registerReader(name, reader);
+        }
+        QWorkers.registerReader(name, reader);
+    }
 }

src/quagga/setupInputStream.ts

@@ -1,7 +1,7 @@
 import { InputStreamType } from "../../type-definitions/quagga";
 
 // TODO: need to create an InputStream typescript interface, so we don't have an "any" in the next line
-export default function setupInputStream(type: InputStreamType, viewport: Element | null, InputStream: any) {
+export default function setupInputStream(type: InputStreamType = 'LiveStream', viewport: Element | null, InputStream: any) {
     switch (type) {
         case 'VideoStream': {
             const video = document.createElement('video');

type-definitions/quagga.d.ts

@@ -391,7 +391,7 @@ export interface QuaggaJSConfigObject {
         /**
          * @default "LiveStream"
          */
-        type: InputStreamType;
+        type?: InputStreamType;
 
         target?: Element | string,