Added debug output option per #681

src/index.d.ts

@@ -73,6 +73,7 @@ declare namespace Tesseract {
     imageColor: boolean;
     imageGrey: boolean;
     imageBinary: boolean;
+    debug: boolean;
   }
   interface RecognizeOptions {
     rectangle: Rectangle

src/worker-script/index.js

@@ -281,11 +281,16 @@ const recognize = async ({
           optionsTess[param] = options[param];
         }
       }
-      if (Object.keys(optionsTess).length > 0) {
-        api.SaveParameters();
-        for (const prop in optionsTess) {
-          api.SetVariable(prop, optionsTess[prop]);
-        }
+    }
+    if (output.debug) {
+      optionsTess["debug_file"] = "/debugInternal.txt";
+      TessModule.FS.writeFile("/debugInternal.txt", "");
+    }
+    // If any parameters are changed here they are changed back at the end
+    if (Object.keys(optionsTess).length > 0) {
+      api.SaveParameters();
+      for (const prop in optionsTess) {
+        api.SetVariable(prop, optionsTess[prop]);
       }
     }
 
@@ -345,6 +350,8 @@ const recognize = async ({
     const result = dump(TessModule, api, workingOutput, {pdfTitle, pdfTextOnly});
     result.rotateRadians = rotateRadiansFinal;
 
+    if (output.debug) TessModule.FS.unlink("/debugInternal.txt");
+
     if (Object.keys(optionsTess).length > 0) {
       api.RestoreParameters();
     }

src/worker-script/utils/dump.js

@@ -219,5 +219,6 @@ module.exports = (TessModule, api, output, options) => {
     psm: enumToString(api.GetPageSegMode(), 'PSM'),
     oem: enumToString(api.oem(), 'OEM'),
     version: api.Version(),
+    debug: output.debug ? TessModule.FS.readFile('/debugInternal.txt', { encoding: 'utf8', flags:"a+" }) : null
   };
 };