36 lines
1.6 KiB
JavaScript
36 lines
1.6 KiB
JavaScript
//#region src/set/reduce.ts
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/**
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* Reduces a Set to a single value by iterating through its elements and applying a callback function.
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*
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* This function iterates through all elements of the Set and applies the callback function to each element,
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* accumulating the result. If an initial value is provided, it is used as the starting accumulator value.
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* If no initial value is provided and the Set is empty, a TypeError is thrown.
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*
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* @template T - The type of elements in the Set.
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* @template A - The type of the accumulator.
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* @param {Set<T>} set - The Set to reduce.
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* @param {(accumulator: A, value: T, value2: T, set: Set<T>) => A} callback - A function that processes each element and updates the accumulator.
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* @param {A} [initialValue] - The initial value for the accumulator. If not provided, the first element in the Set is used.
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* @returns {A} The final accumulated value.
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* @throws {TypeError} If the Set is empty and no initial value is provided.
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*
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* @example
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* const set = new Set([1, 2, 3]);
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* const result = reduce(set, (acc, value) => acc + value, 0);
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* // result will be: 6
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*
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* @example
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* const set = new Set([10, 20]);
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* const result = reduce(set, (acc, value) => acc + value);
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* // result will be: 30 (starts with first value 10)
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*/
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function reduce(set, callback, initialValue) {
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if (initialValue == null && set.size === 0) throw new TypeError("Reduce of empty set with no initial value");
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let accumulator = initialValue;
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for (const value of set) if (accumulator == null) accumulator = value;
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else accumulator = callback(accumulator, value, value, set);
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return accumulator;
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}
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//#endregion
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exports.reduce = reduce;
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