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1/*
2 * Copyright (c) 2024-2025 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16function is_null(v: Object | null | undefined) {
17    return v instanceof null;
18}
19
20function is_obj(v: Object | null | undefined) {
21    return v instanceof Object;
22}
23
24class Foo { };
25
26type nullish_obj = Object | null | undefined;
27type nullish_int = Int | null | undefined;
28type nullish_foo = Foo | null | undefined;
29
30function is_nullish_obj(v: nullish_obj) {
31    return v instanceof nullish_obj;
32}
33
34function is_nullish_int(v: nullish_int) {
35    return v instanceof nullish_int;
36}
37
38function is_nullish_foo(v: nullish_foo) {
39    return v instanceof nullish_foo;
40}
41
42function is_nullish_foo_erased(v: nullish_obj) {
43    return v instanceof nullish_foo;
44}
45
46function main() {
47    const obj = new Object();
48    const foo = new Foo();
49    const boxint = new Int(3);
50
51    assertEQ(is_null(null), true)
52    assertEQ(is_null(undefined), false)
53    assertEQ(is_null(obj), false)
54
55    assertEQ(is_obj(null), false)
56    assertEQ(is_obj(undefined), false)
57    assertEQ(is_obj(obj), true)
58
59    assertEQ(is_nullish_obj(null), true)
60    assertEQ(is_nullish_obj(undefined), true)
61    assertEQ(is_nullish_obj(obj), true)
62    assertEQ(is_nullish_obj(foo), true)
63
64    assertEQ(is_nullish_int(null), true)
65    assertEQ(is_nullish_int(undefined), true)
66    assertEQ(is_nullish_int(boxint), true)
67
68    assertEQ(is_nullish_foo(null), true)
69    assertEQ(is_nullish_foo(undefined), true)
70    assertEQ(is_nullish_foo(foo), true)
71
72    assertEQ(is_nullish_foo_erased(null), true)
73    assertEQ(is_nullish_foo_erased(undefined), true)
74    assertEQ(is_nullish_foo_erased(obj), false)
75    assertEQ(is_nullish_foo_erased(boxint), false)
76    assertEQ(is_nullish_foo_erased(foo), true)
77}
78