Cookbooks
TypeScript
Chapter 5. Good Coding Practices
Handling errors

TypeScript:
Handling errors

How to:

In TypeScript, handling errors often involves try, catch, and finally blocks.

function riskyOperation() {
  throw new Error("Something went wrong!");
}

function handleErrors() {
  try {
    riskyOperation();
  } catch (error) {
    console.error("Caught an error:", error.message);
  } finally {
    console.log("This always runs, error or not.");
  }
}

handleErrors();

Sample output:

Caught an error: Something went wrong!
This always runs, error or not.

Async example with promises:

async function asyncRiskyOperation() {
  return new Promise((resolve, reject) => {
    // Simulate an error
    reject("Failed miserably");
  });
}

async function handleAsyncErrors() {
  try {
    await asyncRiskyOperation();
  } catch (error) {
    console.error("Caught async error:", error);
  }
}

handleAsyncErrors();

Sample output:

Caught async error: Failed miserably

Deep Dive

Error handling has been a cornerstone of programming since its inception. In TypeScript, which builds on JavaScript, error handling became more robust with the introduction of async/await in ECMAScript 2017. Before that, we often relied on callback functions and promises to handle errors in asynchronous code.

An alternative to try/catch in TypeScript is using error boundaries provided by frameworks like React. For server-side handling, we can use middleware in platforms like Express.js to centralize error management.

Implementation-wise, TypeScript doesn’t have its own error handling mechanism but relies on JavaScript’s. Custom error classes can extend the Error class to offer more descriptive error information.

See Also

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