@alwatr/type-helper

A collection of useful TypeScript type helpers — exported as named types, no global augmentation.

Why named exports?

Previous versions used declare global { ... } which required every consumer to add "@alwatr/type-helper" to their tsconfig types array. This caused types to be invisible when navigating to source via go-to-definition in an IDE.

All types are now plain named exports. Import them explicitly, or get them automatically via the bundle packages (@alwatr/core, @alwatr/flux).

Usage

Import directly:

import type {JsonObject, Nullable, DictionaryOpt} from '@alwatr/type-helper';

function save(data: JsonObject): void { ... }
function find(id: string): Nullable<User> { ... }

Or via the bundle packages (no extra import needed):

import type {JsonObject} from '@alwatr/core'; // non-UI bundle
import type {JsonObject} from '@alwatr/flux'; // UI bundle

Available Types

Primitives

| Type | Definition | | ----------- | ---------------------------------------------------------------------- | | Primitive | string \| number \| bigint \| boolean \| symbol \| null \| undefined | | Falsy | false \| '' \| 0 \| 0n \| null \| undefined | | Nullish | null \| undefined |

Functions & Classes

| Type | Description | | ------------------- | ------------------------------------------------ | | Func<Args, R> | Generic function type | | AnyFunc | Alias for any callable | | VoidFunc | Function returning void | | NoopFunc | () => void | | OmitFirstParam<F> | Removes the first parameter from a function type | | Class<T, TArgs> | Class constructor type |

Wrappers & Modifiers

| Type | Description | | -------------------------- | ---------------------------------------------- | | Nullable<T> | T \| null | | Maybe<T> | T \| undefined | | Awaitable<T> | T \| Promise<T> | | SingleOrArray<T> | T \| T[] | | SingleOrReadonlyArray<T> | T \| readonly T[] | | NonUndefined<T> | Excludes undefined from T | | Mutable<T> | Removes readonly from all properties | | StrictlyRequired<T> | Makes all properties required and non-nullable |

Dictionaries

| Type | Description | | ------------------ | ------------------------------------ | | DictionaryOpt<T> | { [key: string]?: T } — sparse map | | DictionaryReq<T> | { [key: string]: T } — dense map |

Object Utilities

| Type | Description | | --------------------- | --------------------------------------------------- | | RequiredKeys<T> | Union of required keys of T | | OptionalKeys<T> | Union of optional keys of T | | Prop<T, K> | Type of property K in T | | ObjectValues<T> | Union of all value types in T | | ArrayItem<T> | Item type of an array type | | Overwrite<M, N> | Overwrites properties of M with N | | Simplify<T> | Flattens intersection types for better IDE tooltips | | HasAddEventListener | Interface for objects with addEventListener |

Deep Recursive

| Type | Description | | ----------------- | ---------------------------------------------------------- | | DeepReadonly<T> | Recursively makes all properties readonly | | DeepRequired<T> | Recursively makes all properties required and non-nullable | | DeepPartial<T> | Recursively makes all properties optional |

JSON

| Type | Description | | --------------- | ------------------------------------------------------ | | JsonPrimitive | string \| number \| boolean \| null | | JsonValue | Any JSON-compatible value | | JsonArray | JSON-compatible array | | JsonObject | JSON-compatible object (DictionaryOpt<JsonValue>) | | Jsonify<T> | Converts a TypeScript type to its JSON-compatible form |

Sponsors

The following companies, organizations, and individuals support Nanolib ongoing maintenance and development. Become a Sponsor to get your logo on our README and website.

Contributing

Contributions are welcome! Please read our contribution guidelines before submitting a pull request.

License

MPL-2.0