34 lines
1.1 KiB
JavaScript
34 lines
1.1 KiB
JavaScript
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//#region src/map/findKey.ts
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/**
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* Finds the first key in a Map for which the predicate function returns true.
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*
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* This function iterates through the entries of the Map and returns the key of the first
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* entry for which the predicate function returns true. If no entry satisfies the predicate,
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* it returns undefined.
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*
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* @template K - The type of keys in the Map.
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* @template V - The type of values in the Map.
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* @param {Map<K, V>} map - The Map to search.
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* @param {(value: V, key: K, map: Map<K, V>) => boolean} doesMatch - A predicate function that tests each entry.
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* @returns {K | undefined} The key of the first entry that satisfies the predicate, or undefined if none found.
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*
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* @example
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* const map = new Map([
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* ['apple', { color: 'red', quantity: 10 }],
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* ['banana', { color: 'yellow', quantity: 5 }],
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* ['grape', { color: 'purple', quantity: 15 }]
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* ]);
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* const result = findKey(map, (value) => value.quantity > 10);
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* // result will be: 'grape'
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*/
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function findKey(map, doesMatch) {
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let result = void 0;
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for (const [key, value] of map) if (doesMatch(value, key, map)) {
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result = key;
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break;
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}
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return result;
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}
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//#endregion
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exports.findKey = findKey;
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