same for omit

test/omit.test.ts

@@ -10,9 +10,9 @@ expectType<{ foo: number; bar: string; biz?: boolean; }>(omit([])(obj));
 expectType<{ bar: string; biz?: boolean }>(omit(['foo'])(obj));
 expectType<{ biz?: boolean }>(omit(['foo', 'bar'])(obj));
 expectType<{}>(omit(['foo', 'bar', 'biz'])(obj));
-// as long as some of the array has valid keys, it will accept it, but will return `never` if there are any invalid keys
-expectType<never>(omit(['baz', 'bar', 'biz'])(obj));
-// if the array is only invalid keys, it will error
+// errors with `never` if array contains some but not all keys on obj
+expectError(omit(['baz', 'bar', 'biz'])(obj));
+// errors (with better message) with array of all unknown keys
 expectError(omit(['baz'])(obj));
 // make sure typed array works
 expectType<{}>(omit([] as (keyof typeof obj)[])(obj));
@@ -26,4 +26,5 @@ expectError(omit(['baz', 'bar', 'biz'], obj));
 expectType<{}>(omit([] as (keyof typeof obj)[], obj));
 
 // Record
+expectType<Record<string, number>>(omit(['foo', 'bar'])({} as Record<string, number>));
 expectType<Record<string, number>>(omit(['foo', 'bar'], {} as Record<string, number>));

test/pick.test.ts

@@ -12,7 +12,7 @@ expectType<{ foo: number; bar: string; }>(pick(['foo', 'bar'])(obj));
 expectType<{ foo: number; bar: string; biz?: boolean }>(pick(['foo', 'bar', 'biz'])(obj));
 // as long as some of the array has valid keys, it will accept it, but will return `never` if there are any invalid keys
 expectError(pick(['baz', 'bar', 'biz'])(obj));
-// if the array is only invalid keys, it will error
+// errors (with better message) with array of all unknown keys
 expectError(pick(['baz'])(obj));
 // make sure typed array works
 expectType<typeof obj>(pick([] as (keyof typeof obj)[])(obj));
@@ -26,4 +26,5 @@ expectError(pick(['baz', 'bar', 'biz'], obj));
 expectType<typeof obj>(pick([] as (keyof typeof obj)[], obj));
 
 // Record
+expectType<Record<string, number>>(pick(['foo', 'bar'])({} as Record<string, number>));
 expectType<Record<string, number>>(pick(['foo', 'bar'], {} as Record<string, number>));

types/omit.d.ts

@@ -1,4 +1,4 @@
 import { ElementOf } from './util/tools';
 
-export function omit<const Names extends readonly PropertyKey[]>(names: Names): <U extends Partial<Record<ElementOf<Names>, any>>>(obj: U) => string extends keyof U ? Record<string, U[keyof U]> : ElementOf<Names> extends keyof U ? Omit<U, ElementOf<Names>> : never;
+export function omit<const Keys extends readonly PropertyKey[]>(names: Keys): <U extends Partial<Record<ElementOf<Keys>, any>>>(obj: ElementOf<Keys> extends keyof U ? U : never) => ElementOf<Keys> extends keyof U ? Omit<U, ElementOf<Keys>> : never;
 export function omit<U, const Names extends readonly (keyof U)[]>(names: Names, obj: U): string extends keyof U ? Record<string, U[keyof U]> : Omit<U, ElementOf<Names>>;