TypeScript and Speech Recognition: Basics


Introduction

Speech recognition is a powerful feature that enables voice-controlled applications. In this guide, we'll explore the basics of using TypeScript with the Web Speech API for speech recognition. We'll create a simple application that converts spoken words into text.


Prerequisites

Before you begin, make sure you have a modern web browser that supports the Web Speech API. You'll also need TypeScript and a code editor. No additional libraries are required for this example.


Getting Started with TypeScript and Speech Recognition

Let's create a basic example of using TypeScript with the Web Speech API for speech recognition.


Step 1: Create an HTML File

Create an HTML file (index.html) to define the structure of the speech recognition application:

<!-- index.html -->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Speech Recognition</title>
</head>
<body>
    <h2>Speech Recognition</h2>
    <button id="start-button">Start Listening</button>
    <p id="output">Spoken Text: </p>
    <script src="app.js"></script>
</body>
</html>

Step 2: Create TypeScript Code

Create a TypeScript file (app.ts) to handle speech recognition:

// app.ts
const startButton = document.getElementById('start-button') as HTMLButtonElement;
const output = document.getElementById('output') as HTMLParagraphElement;
const recognition = new window.SpeechRecognition();
recognition.onresult = (event) => {
    const result = event.results[0][0].transcript;
    output.textContent = `Spoken Text: ${result}`;
};
recognition.onend = () => {
    startButton.disabled = false;
    startButton.textContent = 'Start Listening';
};
startButton.addEventListener('click', () => {
    startButton.disabled = true;
    startButton.textContent = 'Listening...';
    recognition.start();
});

Step 3: Include TypeScript in Your HTML

Include the compiled TypeScript code in your HTML file by referencing the generated JavaScript file:

<script src="app.js"></script>

Conclusion

This basic example demonstrates how to use TypeScript with the Web Speech API for speech recognition. In practice, you can build more advanced voice-controlled applications with features like command recognition and natural language understanding. TypeScript ensures that your code is maintainable and well-structured as your projects become more complex.