| 1 | // Copyright 2017-2022 @polkadot/util authors & contributors
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| 2 | // SPDX-License-Identifier: Apache-2.0
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| 3 |
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| 4 | /**
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| 5 | * @name arrayShuffle
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| 6 | * @description Shuffles the input array (unlike sort, this is not done in-place)
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| 7 | */
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| 8 | export function arrayShuffle(input) {
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| 9 | const result = input.slice();
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| 10 | let curr = result.length; // noop for the single entry
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| 11 |
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| 12 | if (curr === 1) {
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| 13 | return result;
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| 14 | }
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| 15 |
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| 16 | while (curr !== 0) {
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| 17 | // ~~ is more performant than Math.floor
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| 18 | const rand = ~~(Math.random() * curr);
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| 19 | curr--;
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| 20 | [result[curr], result[rand]] = [result[rand], result[curr]];
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| 21 | }
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| 22 |
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| 23 | return result;
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| 24 | } |
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