The infer keyword extracts types within conditional types. Here's how to use it for powerful type manipulation.
Basic Inference
Loading code block...
Array and Tuple Inference
Loading code block...
Promise Unwrapping
Loading code block...
Function Type Manipulation
Loading code block...
Object Type Inference
Loading code block...
String Literal Inference
Loading code block...
Complex Inference Patterns
Loading code block...
Multiple Infer Positions
Loading code block...
Practical Examples
Loading code block...
Best Practices
Usage:
✓ Use infer in conditional types only
✓ Position infer at extraction points
✓ Combine with recursion for complex types
✓ Provide fallback types
Readability:
✓ Name inferred types descriptively
✓ Break complex types into smaller parts
✓ Document inference behavior
✓ Use helper types for common patterns
Performance:
✓ Avoid deeply nested inference
✓ Use constraints to narrow scope
✓ Cache complex inferred types
✓ Test type computation time
Conclusion
The infer keyword enables powerful type extraction within conditional types. Use it to unwrap Promises, extract function parameters, parse template literals, and build flexible utility types. Combined with recursive types and mapped types, infer unlocks advanced type-level programming in TypeScript.