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SkillSnap Official GuideUpdated 7/24/2026
TypeScript
The superset of JavaScript. Master the type system, generics, and utility types to write robust, error-free code.
Core Types & Interfaces
Public APIs & Extendable Objectsinterface
Unions, Aliases, & Tuplestype
Prevent mutation (Immutable)readonly
Property may be undefined? (Optional)
Safer 'any' (Forces checking)unknown
Unreachable code pathnever
Advanced Type Logic
One of multiple typesUnion (|)
Combine multiple typesIntersection (&)
Narrowing via shared 'kind' propertyDiscriminated Union
Get union of object keyskeyof
Get type from valuetypeof
Make array/object readonly literalsas const
Generics & Utilities
Reusable Generic Type<T>
Make all properties optionalPartial<T>
Select subset of propertiesPick<T, K>
Remove subset of propertiesOmit<T, K>
Map keys to specific typeRecord<K, T>
Get function return typeReturnType<T>
Unwrap Promise typeAwaited<T>
Guarding & Narrowing
Custom Type Guardis Type
Check property existencein
Validate without widening typesatisfies
Type Assertion (Use carefully)as Type
Non-null Assertion (Use sparingly)!
Configuration (tsconfig)
Enable all strict checksstrict: true
Disallow implicit 'any'noImplicitAny
Prevent null pointer errorsstrictNullChecks
Speed up compile timeskipLibCheck
Advanced Mapping
{ [K in keyof T]: U }Mapped Types
T extends U ? X : YConditional Types
Extract type within conditioninfer
String interpolation in typesTemplate Literals
React Integration
Extract HTML attributesComponentProps
Functional Component (Deprecated style)React.FC<P>
Generic HooksHook<T>