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TypeScript Advanced Patterns

Advanced TypeScript: discriminated unions, template literals, type inference, and real-world patterns.

Time

Compile-time only

Space

Zero runtime overhead

🧠Mental Model

Type-level programming - write code that validates your other code at compile time.

Verbal cue: Make impossible states impossible.

🎯Recognition Triggers

When you see these patterns in a problem, consider this approach:

advanced TypeScriptdiscriminated unionstemplate literalstype inference

💡Interview Tips

  • 1Discriminated unions are incredibly powerful - show you know them
  • 2Mention how types help with refactoring at scale
  • 3Know when to use as const for literal types

⚠️Common Mistakes

  • Overcomplicating types when simpler solutions exist
  • Not using discriminated unions for state management
  • Fighting the type system instead of working with it