The content of the logger is a function, often named logProgress, which accepts a parameter called event. This event contains progress information about the OCR process.

So, when you pass a function like logProgress as the logger, Tesseract.js will call this function at various points during the OCR process, providing it with updates (the event) about the progress.

.then((result) => { // Handle the successful OCR result console.log('OCR Result:', result.data.text); }) .catch((error) => { // Handle any errors during the OCR process console.error('OCR Error:', error); });

The .then() and .catch() methods are used to handle the result and errors of a promise in JavaScript.

• .then((result) => {...}): This block is executed if the promise resolves successfully. In this case, when the OCR process is successful, the result is passed to the callback function, and you can use it to handle the output (in this case, displaying the recognized text).
• .catch((error) => {...}): This block is executed if the promise is rejected (i.e., if there is an error during the OCR process). The error parameter contains the details of the error, and you can use it to handle the error, like logging it to the console or displaying a message.

Complete Code :

// Import the Tesseract.js libraryconst T = require('tesseract.js');

// Define the image path and language for OCR
const imagePath = ‘./image1.jpeg’;
const language = ‘eng’;

// Define the logger function to track progress
function logProgress(event) {
console.log(event);
}

// Perform the OCR process
T.recognize(imagePath, language, {
logger: logProgress // Use the logger to track progress
})
.then((result) => {
// Handle the successful OCR result
console.log(‘OCR Result:’, result.data.text);
})
.catch((error) => {
// Handle any errors during the OCR process
console.error(‘OCR Error:’, error);
});

We can modify this script if we want display the result on the notepad :

// Import the required librariesconst T = require('tesseract.js');const fs = require('fs'); // Import fs to write to a file

// Define the image path and language for OCR
const imagePath = ‘./image1.jpeg’;
const language = ‘eng’;

// Define the logger function to track progress
function logProgress(event) {
console.log(event);
}

// Perform the OCR process
T.recognize(imagePath, language, {
logger: logProgress // Use the logger to track progress
})
.then((result) => {
// Handle the successful OCR result
const ocrText = result.data.text; // Extract OCR result text
console.log(‘OCR Result:’, ocrText);

// Save the result to a .txt file (Notepad)
fs.writeFile(‘ocr_results.txt’, ocrText, (err) => {
if (err) {
console.error(‘Error writing to file:’, err);
} else {
console.log(‘OCR results saved to ocr_results.txt’);
}
});
})
.catch((error) => {
// Handle any errors during the OCR process
console.error(‘OCR Error:’, error);
});

Explanation:

• fs.writeFile(): This is used to write the OCR result to a .txt file. The first parameter is the file name (ocr_results.txt), and the second is the content to be written (the OCR text).
• The function checks if there’s an error during the writing process. If there’s no error, it confirms that the results have been saved.

After running this script, you should find a file named ocr_results.txt in your project directory containing the recognized text.

While Tesseract.js works great for browser-based projects, enterprise applications often require server-side processing with better performance and accuracy. If you are building a Node.js backend that needs to hand off OCR to a .NET microservice, or if your project evolves into a full-stack .NET application, IronOCR is a solid option.

using IronOcr;var ocr = new IronTesseract();using var input = new OcrInput();input.LoadImage("typed_text.png");var result = ocr.Read(input);File.WriteAllText("ocr_results.txt", result.Text);

IronOCR processes images faster than JavaScript-based solutions for high-volume workloads and includes automatic image enhancement that improves accuracy on typed documents. It supports reading from PDFs, multi-page TIFFs, and even URLs directly.