Conditional Types
Conditional types enable type-level if/else logic, allowing types to change based on conditions.
Conditional Types
Output
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Syntax:
T extends U ? X : Y - if
T extends U, type is X, else Yinfer Keyword
The infer keyword extracts types from conditional types:
type ArrayElement = T extends (infer E)[] ? E : never;
// Extracts element type from array Common Use Cases
- Type extraction: Get return types, parameters
- Type filtering: Exclude null/undefined
- Type transformation: Convert based on conditions
Best Practice: Conditional types power
advanced utility types like ReturnType, Parameters, and NonNullable.
Summary
- Conditional types use
T extends U ? X : Y inferextracts types in conditions- Enable type-level logic
- Foundation of advanced utility types
What's Next?
Congratulations! Module 6 complete. You've mastered advanced type manipulation!
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