//#region src/math/sum.d.ts
/**
 * Calculates the sum of an iterable of numbers, in a single pass and without
 * materializing an intermediate array — so it works on any iterable
 * (generators, `Set`s, …), not just arrays. When the second argument is
 * omitted, the elements are summed directly. When a `getValue` function is
 * provided, each element (along with its zero-based position) is mapped through
 * it first and the resulting numbers are summed.
 *
 * Returns `0` for an empty input.
 * @param items - The iterable to sum. Not mutated.
 * @param getValue - Optional selector that produces the numeric value to add
 * from each element. Receives the element and its zero-based position.
 * @returns The sum of the resolved numeric values, or `0` if `items` is empty.
 * @example
 * // Basic sum of a number array
 * sum([1, 2, 3, 4, 5]);
 * // 15
 * @example
 * // Works on any iterable
 * sum(new Set([1, 2, 3]));
 * // 6
 * @example
 * // With a selector — sum a numeric field of objects
 * sum([{a: 1}, {a: 2}, {a: 3}], (item) => item.a);
 * // 6
 * @example
 * // The selector receives the position too
 * sum([{a: 1}, {a: 2}, {a: 3}], (item, index) => item.a * index);
 * // 8
 * @example
 * // Empty input returns 0
 * sum([]);
 * // 0
 */
declare function sum<T>(items: Iterable<T>, getValue: (element: T, index: number) => number): number;
declare function sum(items: Iterable<number>): number;
//#endregion
export { sum };