| 1 | export default function memoize<Result, Deps extends readonly any[]>(
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| 2 | callback: (...deps: Deps) => Result
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| 3 | ) {
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| 4 | let previous: Deps | undefined;
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| 5 | let result: Result | undefined;
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| 6 |
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| 7 | return (...dependencies: Deps): Result => {
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| 8 | let hasChanged = false;
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| 9 |
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| 10 | if (previous) {
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| 11 | if (previous.length !== dependencies.length) {
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| 12 | hasChanged = true;
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| 13 | } else {
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| 14 | for (let i = 0; i < previous.length; i++) {
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| 15 | if (previous[i] !== dependencies[i]) {
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| 16 | hasChanged = true;
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| 17 | break;
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| 18 | }
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| 19 | }
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| 20 | }
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| 21 | } else {
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| 22 | hasChanged = true;
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| 23 | }
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| 24 |
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| 25 | previous = dependencies;
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| 26 |
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| 27 | if (hasChanged || result === undefined) {
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| 28 | result = callback(...dependencies);
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| 29 | }
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| 30 |
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| 31 | return result;
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| 32 | };
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| 33 | }
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