JavaScript try catch

JavaScript try...catch statement is a way to handle exceptions, or runtime errors, in your code. The "try" block contains the code that may throw an error, and the "catch" block contains the code that will be executed if an error is thrown.

Here's an example of using a try...catch statement:

1try {
2  // code that may throw an error
3  let x = y + z;
4} catch (error) {
5  // code to handle the error
6  console.error(error);
7}

In this example, if the code in the "try" block throws an error (e.g. if "y" or "z" are undefined), the error will be caught by the "catch" block and logged to the console.

The "catch" block takes an argument, which is the error object that was thrown. You can use this error object to access information about the error, such as its message or stack trace.

It's important to note that the "try...catch" statement only catches errors that occur within the "try" block. If an error occurs outside of the "try" block, it will not be caught by the "catch" block.

The "try...catch" statement can be used to handle a wide range of errors, from syntax errors to network errors. It is a crucial tool for debugging and making your code more robust. By using try...catch, you can write more reliable and maintainable code that is less prone to crashes and bugs.

JavaScript custom exceptions by using throw

In JavaScript, you can throw custom exceptions by using the throw statement. Throwing custom exceptions allows you to create custom error messages that are specific to your application, which can be useful for debugging and error handling.

Here's an example of throwing a custom exception:

1function divide(x, y) {
2  if (y === 0) {
3    throw new Error("Cannot divide by zero");
4  }
5  return x / y;
6}
7
8try {
9  let result = divide(10, 0);
10  console.log(result);
11} catch (error) {
12  console.error(error.message);
13}

In this example, the "divide" function throws a custom exception if the value of "y" is zero. The custom exception message "Cannot divide by zero" is passed as the argument to the Error object, which is then thrown using the "throw" statement.

The custom exception is caught by the catch block, which logs the error message to the console.

It's important to note that custom exceptions should be used judiciously and only when necessary. Throwing too many custom exceptions can make your code harder to understand and maintain.

Throwing custom exceptions in JavaScript is a powerful tool for creating custom error messages and handling errors in your code. When used correctly, custom exceptions can help make your code more reliable and easier to debug.