Schlüssel mit as in gemappten Typen umbenennen

Willkommen

Grundlegendes Umbenennen von Schlüsseln

type Prefixed<T> = {
  [K in keyof T as `prefix_${string & K}`]: T[K]
};
type P = Prefixed<{ name: string }>;
// { prefix_name: string }

Schlüssel mit never filtern

type OnlyStrings<T> = {
  [K in keyof T as T[K] extends string ? K : never]: T[K]
};

Getter-Namen generieren

type Getters<T> = {
  [K in keyof T as `get${Capitalize<string & K>}`]: () => T[K]
};
type UserGetters = Getters<{ name: string; age: number }>;
// { getName: () => string; getAge: () => number }

Setter-Namen generieren

type Setters<T> = {
  [K in keyof T as `set${Capitalize<string & K>}`]: (val: T[K]) => void
};

Einen Record-Typ umkehren

type Invert<T extends Record<string, string>> = {
  [K in keyof T as T[K]]: K
};

Bedingte Schlüsselumbenennung

type MethodKeys<T> = {
  [K in keyof T as T[K] extends Function ? K : never]: T[K]
};

Mit Template Literals kombinieren

type Namespaced<T, NS extends string> = {
  [K in keyof T as `${NS}::${string & K}`]: T[K]
};

Symbolschlüssel abbilden

Praxis: FormData-Typ

type FormFields<T> = {
  [K in keyof T as K extends string ? K : never]: string
};

as mit bedingten Typen kombinieren

Kurzer Test

Zusammenfassung