Add documentation

Author: porada

readme.md

@@ -122,6 +122,7 @@ Click the type names for complete docs.
 - [`PartialDeep`](source/partial-deep.d.ts) - Create a deeply optional version of another type. Use [`Partial<T>`](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype) if you only need one level deep.
 - [`PartialOnUndefinedDeep`](source/partial-on-undefined-deep.d.ts) - Create a deep version of another type where all keys accepting `undefined` type are set to optional.
 - [`UndefinedOnPartialDeep`](source/undefined-on-partial-deep.d.ts) - Create a deep version of another type where all optional keys are set to also accept `undefined`.
+- [`UnwrapPartial`](source/unwrap-partial.d.ts) - Revert the `Partial` modifier on an object type.
 - [`ReadonlyDeep`](source/readonly-deep.d.ts) - Create a deeply immutable version of an `object`/`Map`/`Set`/`Array` type. Use [`Readonly<T>`](https://www.typescriptlang.org/docs/handbook/utility-types.html#readonlytype) if you only need one level deep.
 - [`LiteralUnion`](source/literal-union.d.ts) - Create a union type by combining primitive types and literal types without sacrificing auto-completion in IDEs for the literal type part of the union. Workaround for [Microsoft/TypeScript#29729](https://github.com/Microsoft/TypeScript/issues/29729).
 - [`Tagged`](source/tagged.d.ts) - Create a [tagged type](https://medium.com/@KevinBGreene/surviving-the-typescript-ecosystem-branding-and-type-tagging-6cf6e516523d) that can support [multiple tags](https://github.com/sindresorhus/type-fest/issues/665) and [per-tag metadata](https://medium.com/@ethanresnick/advanced-typescript-tagged-types-improved-with-type-level-metadata-5072fc125fcf). (This replaces the previous [`Opaque`](source/tagged.d.ts) type, which is now deprecated.)
@@ -474,6 +475,8 @@ There are many advanced types most users don't know about.
 	// NodeConfig interface.
 	new NodeAppBuilder().config({appName: 'ToDoApp'});
 	```
+
+	`Partial<T>` can be reverted with [`UnwrapPartial`](source/unwrap-partial.d.ts).
 	</details>
 
 - [`Required<T>`](https://www.typescriptlang.org/docs/handbook/utility-types.html#requiredtype) - Make all properties in `T` required.

source/unwrap-partial.d.ts

@@ -1,3 +1,26 @@
+/**
+Revert the `Partial` modifier on an object type.
+
+Use case: Infer the underlying type `T` when only `Partial<T>` is available or the original type may not be directly accessible.
+
+@example
+```
+import type {UnwrapPartial} from 'type-fest';
+
+type Config = Partial<{
+	port: number;
+	host: string;
+	secure?: boolean;
+}>;
+
+type InitializedConfig = UnwrapPartial<Config>;
+//=> { port: number; host: string; secure?: boolean }
+```
+
+If the provided type isn’t of `Partial<T>`, `UnwrapPartial` has no effect on the original type.
+
+@category Object
+*/
 export type UnwrapPartial<PartialObjectType> =
 	PartialObjectType extends Partial<infer ObjectType>
 		? (