Basic TypeScript

Home / Topic / Basic TypeScript / Error Handling in TypeScript

Error Handling in TypeScript

Proper error handling is essential for building robust and secure applications. TypeScript, being a superset of JavaScript, inherits JavaScript's error handling capabilities but adds stricter typing that helps us manage errors in a more controlled way.

this image shows a cover for error handling this image shows a cover for error handling

Types of Errors

In TypeScript, we can handle different types of errors, including:

Compile-time Errors: These errors are detected by the TypeScript compiler and prevent incorrect code from being executed. For example, typing errors.
Runtime Errors: These errors occur during code execution and are handled using try and catch blocks.

Compile-time Error Example

typescript

"In this example, TypeScript generates a compile-time error because we are trying to assign a string to a variable of type number."

Runtime Error Handling

Runtime errors can be caught using try, catch, and finally blocks. This allows us to handle errors in a more controlled way, ensuring that our program can recover or properly handle exceptions.

`try` and `catch` Example

typescript

"In this example, the divide function throws an error if an attempt is made to divide by zero. The try block attempts to execute the function and the catch block catches the error, displaying the corresponding message in the console."

`finally` Block

The finally block always executes, regardless of whether an error occurred. This is useful when we need to execute code that must run no matter what, like releasing resources or closing connections.

typescript

"In this example, the finally block runs after the try and catch blocks, regardless of whether an error occurred. In this case, it prints Operation completed."

Error Typing

One of the advantages of TypeScript is that we can define types for the errors we want to handle, making the code more predictable and secure.

Custom Error Typing

We can create our own error types to handle them more specifically in our applications.

typescript

"This example shows how to create a custom error class called DivisionError. When we throw this error, we can catch and handle it specifically in the catch block."

Asynchronous Errors

When working with asynchronous operations, such as API calls, it is also important to handle errors properly. Promises and asynchronous functions provide mechanisms to catch errors.

Error Handling with Promises

typescript

"In this example, we use the then method to handle the response of an API call. If the response is not successful, an error is thrown and caught in the catch block."

Error Handling with `async` and `await`

Asynchronous functions with async and await allow us to write more readable code and handle errors similarly to synchronous functions.

typescript

"Here, we use an asynchronous function to make an API call. If an error occurs during the execution of the function, it is caught in the try catch block."

Conclusion

In this chapter, we have learned how to handle errors in TypeScript, both at compile-time and runtime. We have also seen how to type custom errors and handle asynchronous errors, allowing us to build more robust and secure applications.

Back to previous chapter

Mark as read and continue