Error handling and debugging are crucial parts of any programming language, and JavaScript is no exception. When writing code, it is important to anticipate and handle errors that may occur during the execution of the program. JavaScript provides several ways to handle errors and debug code.

1. Error Handling:

JavaScript provides a built-in try...catch statement for handling errors. The try block contains the code that may throw an error, and the catch block contains the code that handles the error. If an error is thrown in the try block, the catch block is executed.

Example program:

try {
  let num = "hello";
  num.toFixed(2);
} catch (error) {
  console.error(error);
}

In the above example, we create a try...catch block that attempts to call the toFixed() method on a string. Since toFixed() is a method for numbers, this will result in an error. The catch block catches the error and logs it to the console.

2. Debugging:

Debugging is the process of finding and fixing errors in code. JavaScript provides several built-in tools for debugging code, including the console.log() method and the browser developer tools.

Example program:

let num1 = 10;
let num2 = 0;

try {
  if (num2 === 0) {
    throw new Error("Divide by zero error");
  }
  let result = num1 / num2;
  console.log(`Result: ${result}`);
} catch (error) {
  console.error(error);
}

In the above example, we create a try...catch block that attempts to divide num1 by num2. Since num2 is 0, this will result in a divide by zero error. We throw a new Error object with a custom error message. We then catch the error and log it to the console.

To debug the code, we can use the console.log() method to log variables and values to the console. We can also use the browser developer tools to set breakpoints, step through code, and inspect variables and values.

In Visual Studio Code, we can set breakpoints by clicking on the left-hand side of the line number in the editor. When we run the code in debug mode, the program will stop at the breakpoint, allowing us to inspect variables and values.

Overall, error handling and debugging are important skills for any JavaScript developer. By handling errors properly and using effective debugging techniques, we can write code that is more reliable and easier to maintain.