TypeScript Utility Types

References

• Link to TypeScript Utility function documentation

Notes

TypeScript offers a variety of utility types to facilitate common type transformations. Here's a summary of some of the key utility types:

• Partial<Type>: Constructs a type with all properties of Type set to optional, representing all subsets of a given type.
• Required<Type>: Constructs a type with all properties of Type set to required, the opposite of Partial.
• Readonly<Type>: Constructs a type with all properties of Type set to readonly, preventing modification of the properties.
• Record<Keys, Type>: Constructs a type with a set of properties Keys of type Type.
• Pick<Type, Keys>: Constructs a type by picking a set of properties Keys from Type.
• Omit<Type, Keys>: Constructs a type by omitting a set of properties Keys from Type.
• Exclude<UnionType, ExcludedMembers>: Constructs a type by excluding from UnionType all union members that are assignable to ExcludedMembers.
• Extract<UnionType, ExtractedMembers>: Constructs a type by extracting from UnionType all union members that are assignable to ExtractedMembers.
• NonNullable<Type>: Constructs a type by excluding null and undefined from Type.
• Parameters<Type>: Constructs a tuple type from the types used in the parameters of a function type Type.
• ConstructorParameters<Type>: Constructs a tuple or array type from the types used in the parameters of a constructor function type Type.
• ReturnType<Type>: Constructs a type consisting of the return type of function Type.
• InstanceType<Type>: Constructs a type consisting of the instance type of a constructor function type Type.
• ThisParameterType<Type>: Extracts the type of the this parameter for a function type, or unknown if the function type has no this parameter.
• OmitThisParameter<Type>: Removes the this parameter from Type.
• ThisType<Type>: Used to specify the type of this in methods of an object.
• Awaited<Type>: Used to model operations like await in async functions, recursively unwrapping Promises.