Error Handling & Type Safety

📖 Learning Objectives

Understand Rust's error handling philosophy, learn to use Result and Option types, master error propagation patterns, and contrast with JavaScript's exception handling mechanism.

---

🎯 Error Handling Philosophy Comparison

JavaScript's Exception Handling

JavaScript uses the try-catch mechanism for exception handling:

Rust's Error Handling

Rust uses the type system for error handling, without exceptions:

Error Handling Differences

1. Exceptions vs Types: JavaScript uses exceptions, Rust uses type system
2. Runtime vs Compile-time: JavaScript runtime checks, Rust compile-time checks
3. Recoverable vs Unrecoverable: Rust distinguishes recoverable errors (Result) and unrecoverable errors (panic)
4. Explicit vs Implicit: Rust forces explicit error handling, JavaScript can ignore exceptions

---

📦 Option Type

Handling Potentially Empty Values

---

🔄 Result Type

Handling Potentially Failing Operations

---

🎯 Best Practices for Error Handling

Error Handling Patterns Comparison

Advanced Error Handling Libraries

In real-world projects, to simplify error definition and handling, the Rust community provides excellent error handling libraries, such as:

• thiserror: Simplifies the definition of custom error types, especially when errors need to contain additional information or derive from other error types. It automatically implements Display and Error traits via macros.
• anyhow: Simplifies error propagation, especially in application-level code. It provides a simple Result type alias anyhow::Result<T> and allows you to easily convert various error types to anyhow::Error.

These libraries can significantly reduce boilerplate code for error handling, improving code readability and maintainability.

---

🎯 Exercises