TypeScript uses structural typing rather than nominal typing, meaning the compiler checks object shape (field names and types) rather than type names. This differs from languages like Java or C# where type identity matters. Structural typing enables concise, flexible code — especially in functional styles — but developers must remember TypeScript is transpiled, not compiled: types are not enforced at runtime. When handling external data (e.g., HTTP requests), you should always validate and reconstruct objects explicitly rather than trusting deserialized input, to avoid unexpected fields or unsafe behavior.
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