Merge pull request #56 from cuppachino/require-some

✨add `RequireSome` type

.changeset/stale-falcons-rest.md

@@ -0,0 +1,5 @@
+---
+"@cuppachino/type-space": patch
+---
+
+✨ Feat `RequireSome` type

README.md

@@ -106,6 +106,7 @@ The source code is fully tsdoc'd, so you can use your IDE's intellisense to refe
 - [`Mutable`](src/mutable.ts): Recursively removes the `readonly` modifier from all properties of a type.
 - [`PartialSome`](src/partial-some.ts): Return a new type that allows the specified keys to be undefined.
 - [`PickAll`](src/pick-all.ts): Extract properties from _all_ members in a union, missing properties default to `| undefined`.
+- [`RequireSome`](src/require-some.ts): Return a new type requiring the selected keys.
 - [`Simplify`](src/simplify.ts): Simplify a type by mapping over its inferred properties - use when `Combine` cannot infer a deep type.
 - [`Subset`](src/subset.ts): TypeScript equivalent of `⊆`.
 - [`UnionLiteral`](src/union-literal.ts): Create a union from a literal and primitive type without losing the literal type.

src/index.ts

@@ -16,6 +16,7 @@ export type { Mutable } from 'type-space/mutable'
 export type { ParseNumberLiteral } from 'type-space/parse-number-literal'
 export type { PartialSome } from 'type-space/partial-some'
 export type { PickAll } from 'type-space/pick-all'
+export type { RequireSome } from 'type-space/require-some'
 export type { Zip } from 'type-space/zip'
 
 // strings

src/require-some.ts

@@ -0,0 +1,22 @@
+import type { Combine } from './combine'
+
+/**
+ * Returns a new type where some properties `K` of `T` are required.
+ * The rest are left as-is.
+ *
+ * @example
+ * ```
+ * type Data = {
+ * a?: string;
+ * b?: string;
+ * };
+ * type Ex = RequireSome<Test, "a">;
+ * ```
+ */
+export type RequireSome<T, K extends keyof T> = Combine<
+	{
+		[P in keyof T as Extract<P, K>]-?: T[P]
+	} & {
+		[P in keyof T as Exclude<P, K>]: T[P]
+	}
+>