export declare enum OPERATION_TYPES {
    SUM = "SUM",
    PRODUCT = "PRODUCT",
    DIFFERENCE = "DIFFERENCE"
}
/**
 * Operate on the `values` up to the given `index` based the specific `operation`.
 * If the `index` is not given it operates to the end.
 *
 * @param type
 * @param values
 * @param index
 */
export declare const operation: (type: keyof typeof OPERATION_TYPES, values: number[], index?: number) => number;
/**
 * Sum the `values` up to the given `index`.
 * If the `index` is not given it sums to the end.
 *
 * @param values
 * @param index
 */
export declare const sum: (values: number[], index?: number) => number;
/**
 * Multiply the `values` up to the given `index`.
 * If the `index` is not given it multiplies to the end.
 *
 * @param values
 * @param index
 */
export declare const product: (values: number[], index?: number) => number;