Real-world mechanisms, state management, edge cases, performance trade-offs, and practical coding.
[key: string]: any): Define arbitrary properties on objects. Flexible, but cannot restrict keys to a specific finite union of literals.[K in Keys]: T): Use iteration to construct an object type based on a source union of keys. Allow dynamic property construction with full type safety.type Shape = { kind: "circle"; radius: number } | { kind: "square"; side: number };
switch blocks based on checking the literal tag.interface Config<T = string> { value: T; }
interface A extends B {} represents static OOP-style inheritance. If properties overlap with incompatible types, it throws a compile-time error.T extends U ? X : Y), checking if a type is assignable to/compatible with another structure. Highly dynamic.+ or -): Modify existing property constraints during mapping.-readonly: Removes readonly from all properties.-?: Removes optionality, making all properties strictly required.You've completed the 5 free sample questions. Get unrestricted lifetime access to every question, model answer, implementation challenge, and all 27+ technologies for a single payment.
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