Result Pattern (Ok / Err)

The Result pattern represents operations that can succeed (Ok) or fail (Err) using explicit discriminated union types instead of throwing runtime exceptions.

1. Introduction & Architecture

2. Deep Dive & Core Concepts

Using Result forces caller functions to check result.ok before accessing data, making error handling explicit in component and service function signatures.

3. Basic Code Example

4. Advanced Production Patterns

5. Interactive Code Playground

type Result = { ok: true; data: T } | { ok: false; error: E };
function divide(a: number, b: number): Result {
  if (b === 0) return { ok: false, error: "Cannot divide by zero" };
  return { ok: true, data: a / b };
}
const r = divide(10, 2);
if (r.ok) console.log("Result:", r.data);

6. Common Pitfalls & Edge Cases

7. Interview Q&A & Quizzes

Q: What is the main advantage of Result over throw/catch?

A: Errors become explicit in the function signature type, forcing callers to handle failures at compile time.

8. Summary Comparison Table