@cozka/utils-niche-types

A library that collects niche TypeScript type definitions.

日本語の README はこちら

Installation

npm install @cozka/utils-niche-types

Usage

Prefixed<PREFIX, RECORD, KEYS>

Adds a camel-case prefix to specified properties.

Parameters

• PREFIX: The prefix to be applied.
• RECORD: The record type containing properties.
• KEYS: The properties to which the prefix should be applied (defaults to all properties).

Example

type Original = {
  name: string;
  age: number;
};

type PrefixedType = Prefixed<'user', Original>;
// Result:
// {
//   userName: string;
//   userAge: number;
// }

PrefixedUnion<PREFIX, UNION, KEYS>

Adds a camel-case prefix to specified values in a union type.

Parameters

• PREFIX: The prefix to be applied.
• UNION: The target union type.
• KEYS: The values to which the prefix should be applied (defaults to all values).

Example

type Status = 'active' | 'inactive' | 'pending';
type PrefixedStatus = PrefixedUnion<'is', Status>;
// Result: 'isActive' | 'isInactive' | 'isPending'

Keys<RECORD, TYPE>

Creates a union type of keys that have a specified value type.

Parameters

• RECORD: The target record.
• TYPE: The value type to filter keys (defaults to any).

Example

type Data = {
  id: number;
  name: string;
  age: number;
};

type NumberKeys = Keys<Data, number>;
// Result: 'id' | 'age'

License

MIT