23 lines
472 B
JavaScript
23 lines
472 B
JavaScript
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/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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/**
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* @template K
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* @template V
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* @param {Map<K, V>} map a map
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* @param {K} key the key
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* @param {function(): V} computer compute value
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* @returns {V} value
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*/
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exports.provide = (map, key, computer) => {
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const value = map.get(key);
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if (value !== undefined) return value;
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const newValue = computer();
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map.set(key, newValue);
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return newValue;
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};
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