export declare type Collection = Array<{
    [key: string]: any;
}>;
declare type Fields = string[] | string;
/**
 * stackByFields
 *
 * D3's `stack` groups each series' data together but we sometimes we want the
 * stacked groups to remain grouped as in the original normalized data. This
 * function helps achieve that.
 *
 * @param {object[]} collection - normalized data you want to operate on
 * @param {string[]} fields - fields to pluck off for the y data
 * @return {array[]} - array of arrays, one for row in the original `collection`
 */
export declare function stackByFields(collection: Collection, fields: Fields): Array<Array<[number, number]>>;
/**
 * extractFields
 *
 * This will return the data in a similar format to stackByFields but without
 * the stacking.
 *
 * @param {object[]} collection - normalized data you want to operate on
 * @param {string[]} fields - fields to pluck off for the y data
 * @return {array[]} - array of arrays, one for each field
 */
export declare function extractFields(collection: Collection, fields: Fields, minDomainValue?: number): Array<Array<[number, number]>>;
/**
 * groupByFields
 *
 * This will return the data in a similar format to d3Shape.stack
 * but without the stacking of the data.
 *
 * @param {object[]} collection - normalized data you want to operate on
 * @param {string[]} fields - fields to pluck off for the y data
 * @return {array[]} - array of arrays, one for each field
 */
export declare function groupByFields(collection: Collection, fields: Fields): any[][];
/**
 * byFields
 *
 * Takes a collection of data and returns an array of all the fields off that
 * collection.
 *
 * @param {object[]} collection
 * @param {string[]} fields
 * @return {array}
 */
export declare function byFields(collection: Collection, fields: Fields): object[];
/**
 * nearest
 *
 * Divide and conquer algorithm that helps find the nearest element to `value`
 * in `nums`
 *
 * @param {number[]} nums - sorted array of numbers to search through
 * @param {number} value - value you're trying to locate the nearest array element for
 * @return {number} - the nearest array element to the value
 */
export declare function nearest(nums: number[], value: number): number | undefined;
/**
 * minByFields
 *
 * Returns the minimum element from a collection by a set of fields.
 *
 * @param {object[]} collection
 * @param {string[]} fields
 * @return {any}
 */
export declare function minByFields(collection: Collection, fields: Fields): object | undefined;
/**
 * maxByFields
 *
 * Returns the maximum element from a collection by a set of fields.
 *
 * @param {object[]} collection
 * @param {string[]} fields
 * @return {any}
 */
export declare function maxByFields(collection: Collection, fields: Fields): object | undefined;
/**
 * maxByFieldsStacked
 *
 * Returns the max sum of a set of fields from a collection
 *
 * @param {object[]} collection
 * @param {string[]} fields
 * @return {any}
 */
export declare function maxByFieldsStacked(collection: Collection, fields: Fields): number | undefined;
/**
 * discreteTicks
 *
 * Returns `count` evenly spaced, representative values from the `array`.
 *
 * @param {array} array
 * @param {number} size - should be greater than 1
 * @return {array}
 */
export declare function discreteTicks<T>(array: T[], count?: number | undefined | null): T[];
/**
 * transformFromCenter
 *
 * Scaling paths from their center is tricky. This function
 * helps do that be generating a translate/scale transform
 * string with the correct numbers.
 *
 * @param {number} x - the x data point where you want the path to be centered at
 * @param {number} y - the y data point where you want the path to be centered at
 * @param {number} xCenter - the x coordinate of the center of the path you're trying to transform
 * @param {number} yCenter - the x coordinate of the center of the path you're trying to transform
 * @param {number} scale - number to scale to, 2 would be 2x bigger
 * @return {string} - transform string
 */
export declare function transformFromCenter(x: number, y: number, xCenter: number, yCenter: number, scale: number): string;
/**
 * formatDate
 *
 * This function was written to be used for tick formatting with d3 time
 * scales.
 *
 * @param {date} date - input date
 * @return {string} - formatted date
 */
export declare function formatDate(date: Date): string;
export {};