feat(types): add PickAny type, symmetric with PickOne

src/index.ts

@@ -15,3 +15,4 @@ export * from './companions/pick';
 export * from './types/Literalize';
 export * from './wrappers/withAssure';
 export * from './checks/isKeyOf';
+export * from './types/PickAny';

src/types/PickAny.test.ts

@@ -0,0 +1,48 @@
+import { PickAny } from './PickAny';
+
+describe('PickAny', () => {
+  it('should constrain type correctly', async () => {
+    const findFlowers = async (
+      input: PickAny<{
+        color: {
+          petals: string;
+        };
+        size: {
+          choice: 'LARGE' | 'SMALL';
+        };
+      }>,
+    ) => {
+      // ...
+    };
+
+    // you can find by color
+    await findFlowers({
+      color: {
+        petals: 'white',
+      },
+    });
+
+    // you can find by size
+    await findFlowers({
+      size: {
+        choice: 'LARGE',
+      },
+    });
+
+    // you can find by both
+    await findFlowers({
+      color: {
+        petals: 'white',
+      },
+      size: {
+        choice: 'LARGE',
+      },
+    });
+
+    // you can't find by neither
+    await findFlowers({
+      // @ts-expect-error - cant be neither
+      size: {},
+    });
+  });
+});

src/types/PickAny.ts

@@ -0,0 +1,14 @@
+/**
+ * creates a type which requires specifying at least one, or more, key of an object
+ *
+ * ref:
+ * - https://stackoverflow.com/a/49725198/3068233
+ */
+export type PickAny<TObj, TKeys extends keyof TObj = keyof TObj> = Pick<
+  TObj,
+  Exclude<keyof TObj, TKeys>
+> &
+  {
+    [K in TKeys]-?: Required<Pick<TObj, K>> &
+      Partial<Pick<TObj, Exclude<TKeys, K>>>;
+  }[TKeys];

src/types/PickOne.test.ts

@@ -36,11 +36,18 @@ describe('PickOne', () => {
     });
 
     // you can't find by both
-    // await findWrench({
-    //   size: {
-    //     metric: { millimeters: 16 },
-    //     imperial: { inches: '5/16' },
-    //   },
-    // });
+    await findWrench({
+      // @ts-expect-error - cant be both
+      size: {
+        metric: { millimeters: 16 },
+        imperial: { inches: '5/16' },
+      },
+    });
+
+    // you can't find by neither
+    await findWrench({
+      // @ts-expect-error - cant be neither
+      size: {},
+    });
   });
 });