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