Blog

Mert Özen's blog posts on software development, backend, frontend, and DevOps.

Series

.NET Core Web API 36 Angular 31 JavaScript Basics 19 JavaScript Intermediate 18 JavaScript Advanced 16 TypeScript Basics 14 TypeScript Intermediate 14 TypeScript Advanced 12

2 posts found #discriminated-union

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Frontend PART 12

Error Handling in TypeScript: unknown in catch, Narrowing Errors and the Result Pattern

We look at why the catch variable is unknown, narrowing with instanceof Error, custom error classes, Promise pitfalls, and modeling errors with Result and discriminated unions.

3 Nov 2026 9 min 1

Frontend PART 09

Narrowing in TypeScript: Shrinking Unions with Control Flow Analysis

We see how TypeScript narrows unions through control flow analysis: typeof, truthiness, equality, in and instanceof checks, discriminated unions and exhaustive checks with never.

3 Nov 2026 8 min 1