iterate-objects-safely

SKILL.md

Iterating over objects in TypeScript is surprisingly tricky. The for...in loop infers keys as string rather than the object's keys, leading to indexing errors. This happens because objects can have additional properties beyond their declared type (structural typing), and for...in includes inherited properties.

Understanding safe iteration patterns helps you avoid any types and type assertions while correctly handling object traversal.

Use Object.entries for safe iteration over any object. Use for...in with keyof assertions only when you know the exact shape. Consider Map for guaranteed type safety.

객체 키와 값을 반복할 때 사용합니다. for...in 루프가 유형 오류를 생성할 때 사용하십시오. Object.entries가 모든 유형을 반환할 때 사용합니다. 프로토타입 오염 문제를 처리할 때 사용합니다. Map과 객체를 고려할 때 사용합니다. 출처: marius-townhouse/effective-typescript-skills.

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