In this article, i'm going to cover 10 typescript utilities every developer should know.
- Partial type
- Required type
- Readonly
- Pick
- Omit
- Record
- Exclude
- Extract
- NonNullable
- Return type
1- Partial type
Type Person = { name: string; age: number; gender: string; address: string; } // Partial<T> type Partial sets all properties // of Person to optional type PartialPerson = Partial<Person>; 2-Required
// Required<T> all properties of `RequiredPerson` // are required type RequiredPerson = Required<Person>; 3-Readonly
// Readonly<T>: Creates a type with all properties // of T set to readonly. type ReadonlyPerson = Readonly<Person>; 4-Pick
// Creates a type by picking only the specified // properties K from T. type PersonName = Pick<Person, 'name'>; 5-Omit
// Omit<T,K> Creates a type by omitting the specified // properties K from T. type PersonWithoutAge = Omit<Person, 'age'>; 6-Record
// Record<K,T> Creates a type with keys of type // K and values of type T. type StringRecord = Record<string, Person>; 7-Exclude
// Exclude<T, U>: Creates a type by excluding all types // from T that are assignable to U. // string is excluded from the union type type NumbersOnly = Exclude<number | string, string>; 8-Extract
// Extract<T, U> Creates a type by extracting all types // from T that are assignable to U. // string is extract from the union type type StringOnly = Extract<number | string, string>; 9-NonNullable
// NonNullable<T>: Creates a type by removing null and undefined from T. // null and undefined are excluded from the union type type NonNullString = NonNullable<string | null | undefined>; 10-ReturnType
// ReturnType<T>: Obtains the return type of a function type. type MyFunctionReturnType = ReturnType<MyFunction>;