fix: keep prototype null-ness

If the subject is created using `record()`,
`pick()` and `omit()` will maintain that.

ts/object/omit.spec.ts

@@ -1,4 +1,4 @@
-import { assertType, Equal, Except, isType, Omit, omit } from '../index.js'
+import { assertType, Equal, Except, isType, Omit, omit, record } from '../index.js'
 
 describe('Omit<T, K>', () => {
   test('work with primitive types', () => {
@@ -92,12 +92,17 @@ describe(`${omit.name}()`, () => {
     isType.equal<true, Record<string, any>, typeof r>()
   })
 
-  it('more than 12', () => {
+  it('supports more than 12 arguments', () => {
     const actual = omit({ a: 1, b: 1, c: 1 }, 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'b')
 
     expect(actual).toEqual({ c: 1 })
     assertType.isTrue(true as Equal<keyof typeof actual, 'c'>)
   })
+
+  it('maintains the prototype null-ness', () => {
+    expect(Object.getPrototypeOf(omit({ a: 1 }, 'a'))).not.toEqual(null)
+    expect(Object.getPrototypeOf(omit(record({ a: 1 }), 'a'))).toEqual(null)
+  })
 })
 
 describe('Except()', () => {

ts/object/omit.ts

@@ -1,6 +1,7 @@
-import { AnyRecord, record, reduceByKey } from '../object/index.js'
+import { AnyRecord, reduceByKey } from '../object/index.js'
 import { UnionKeys } from '../UnionKeys.js'
 import { Pick } from './pick.js'
+import { record } from './record.js'
 
 // by Titian Cernicova-Dragomir
 // https://github.com/microsoft/TypeScript/issues/28339#issuecomment-463577347
@@ -33,5 +34,5 @@ export function omit<T extends AnyRecord>(subject: T, ...props: Array<UnionKeys<
   return reduceByKey(subject, (p, k) => {
     if (props.indexOf(k) === -1) p[k] = subject[k]
     return p
-  }, record())
+  }, Object.getPrototypeOf(subject) === null ? record() : {})
 }

ts/object/pick.spec.ts

@@ -1,12 +1,4 @@
-import { assertType, canAssign, Equal, Pick, pick } from '../index.js'
-
-describe(`${pick.name}()`, () => {
-  it('picks properties from object', () => {
-    const actual = pick({ a: 1, b: 2 }, 'a')
-
-    expect(actual).toEqual({ a: 1 })
-  })
-})
+import { assertType, canAssign, Equal, isType, Pick, pick, record } from '../index.js'
 
 describe(`Pick<T, K>`, () => {
   test('distributive pick', () => {
@@ -68,3 +60,24 @@ describe(`Pick<T, K>`, () => {
     assertType.isTrue(true as Equal<K, never>)
   })
 })
+
+describe(`${pick.name}()`, () => {
+  it('picks properties from object', () => {
+    const actual = pick({ a: 1, b: 2 }, 'a')
+
+    expect(actual).toEqual({ a: 1 })
+  })
+
+  it('supports more than 12 arguments', () => {
+    const actual = pick({ a: 1, b: 1, c: 1 }, 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'b')
+
+    expect(actual).toEqual({ a: 1, b: 1 })
+    isType.equal<true, 'a' | 'b', keyof typeof actual>()
+  })
+
+  it('maintains the prototype null-ness', () => {
+    expect(Object.getPrototypeOf(pick({ a: 1 }, 'a'))).not.toEqual(null)
+    expect(Object.getPrototypeOf(pick(record({ a: 1 }), 'a'))).toEqual(null)
+  })
+})
+

ts/object/pick.ts

@@ -1,6 +1,6 @@
-import { record } from 'type-plus'
 import { UnionKeys } from '../UnionKeys.js'
 import type { AnyRecord } from './AnyRecord.js'
+import { record } from './record.js'
 import { reduceByKey } from './reduceKey.js'
 
 export function pick<T extends AnyRecord, P1 extends UnionKeys<T>>(subject: T, prop1: P1): Pick<T, P1>
@@ -20,7 +20,7 @@ export function pick<T extends AnyRecord>(subject: T, ...props: Array<UnionKeys<
   return reduceByKey(subject, (p, k) => {
     if (props.indexOf(k) >= 0) p[k] = subject[k]
     return p
-  }, record())
+  }, Object.getPrototypeOf(subject) === null ? record() : {})
 }
 
 /**