1 | // Copyright 2017-2022 @polkadot/util authors & contributors
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2 | // SPDX-License-Identifier: Apache-2.0
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3 | import { isFunction } from "./is/function.js";
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4 |
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5 | /**
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6 | * @name assert
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7 | * @summary Checks for a valid test, if not Error is thrown.
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8 | * @description
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9 | * Checks that `test` is a truthy value. If value is falsy (`null`, `undefined`, `false`, ...), it throws an Error with the supplied `message`. When `test` passes, `true` is returned.
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10 | * @example
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11 | * <BR>
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12 | *
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13 | * ```javascript
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14 | * const { assert } from '@polkadot/util';
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15 | *
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16 | * assert(true, 'True should be true'); // passes
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17 | * assert(false, 'False should not be true'); // Error thrown
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18 | * assert(false, () => 'message'); // Error with 'message'
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19 | * ```
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20 | */
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21 | export function assert(condition, message) {
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22 | if (!condition) {
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23 | throw new Error(isFunction(message) ? message() : message);
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24 | }
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25 | }
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26 | /**
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27 | * @name assertReturn
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28 | * @description Returns when the value is not undefined/null, otherwise throws assertion error
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29 | */
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30 |
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31 | export function assertReturn(value, message) {
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32 | assert(value !== undefined && value !== null, message);
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33 | return value;
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34 | }
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35 | /**
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36 | * @name assertUnreachable
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37 | * @description An assertion helper that ensures all codepaths are followed
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38 | */
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39 |
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40 | export function assertUnreachable(x) {
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41 | throw new Error(`This codepath should be unreachable. Unhandled input: ${x}`);
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42 | } |
\ | No newline at end of file |