xref: /aosp_15_r20/development/tools/winscope/src/common/assert_utils.ts (revision 90c8c64db3049935a07c6143d7fd006e26f8ecca)
1/*
2 * Copyright (C) 2023 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17export function assertDefined<A>(
18  value: A | null | undefined,
19  lazyErrorMessage?: () => string,
20): A {
21  if (value === undefined || value === null) {
22    throw new Error(
23      lazyErrorMessage
24        ? lazyErrorMessage()
25        : `Expected value, but found '${value}'`,
26    );
27  }
28  return value;
29}
30
31export function assertTrue(value: boolean, lazyErrorMessage?: () => string) {
32  if (!value) {
33    throw new Error(
34      lazyErrorMessage ? lazyErrorMessage() : 'Expected value to be true',
35    );
36  }
37}
38
39// Ensure at compile-time that a certain line is not reachable.
40// E.g. make sure that a switch/case handles all possible input values.
41export function assertUnreachable(x: never): never {
42  throw new Error('This line should never execute');
43}
44