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When You Get Stuck on Union Types, You Need Type Narrowing

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Key summary

2 min read
  1. The article explains how to safely handle TypeScript union types by narrowing values with conditionals.

  2. It covers practical type guards such as `typeof`, `instanceof`, and the `in` operator.

  3. These patterns help distinguish `string`, `number`, and object-like values more accurately at runtime.

  4. Using type narrowing improves error prevention and lets TypeScript infer types more effectively.

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