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Exported types

Transform​

Represents a synchronous step from one value to another.

type Transform<Input, Output> = (value: Input) => Output;
const selectName: Transform<{name: string}, string> = user => user.name;

Renamed​

Maps an input object type through a rename map.

type ApiUser = {user_id: number; full_name: string};
type User = Renamed<ApiUser, {user_id: 'id'; full_name: 'name'}>;
// {id: number; name: string}

Picked and Omitted​

These distributive types represent the object shapes returned by pick and omit. They preserve property modifiers and distribute across union inputs.

type PublicUser = Picked<ApiUser, 'user_id'>;
type WithoutName = Omitted<ApiUser, 'full_name'>;

Normalizer types​

  • BuiltInNormalizer is the union of supported named specs.
  • Normalizer<Value, Output> describes a custom callback receiving a value and property key.
  • NormalizerSpec accepts either a built-in spec or custom callback.
const trim: Normalizer<unknown, string | null> = value =>
  typeof value === 'string' ? value.trim() : null;