Sometimes, we want to extend the Error class with TypeScript.

In this article, we’ll look at how to extend the Error class with TypeScript.

How to extend the Error class with TypeScript?

To extend the Error class with TypeScript, we can use the extend keyword.

For instance, we write

class FooError extends Error {
  constructor(m: string) {
    super(m);
  }

  sayHello() {
    return this.message;
  }
}

to create the FooError class that inherits from the Error class by adding extends Error.

In the constructor, we call super parent constructor with the arguments required by Error.

And then we add the sayHello method that’s exclusive to the FooError class.

Conclusion

To extend the Error class with TypeScript, we can use the extend keyword.