export declare function flatten<T>(xss: T[][]): T[];
export declare function distinct<T>(xs: T[]): T[];
export declare function minAbs(xs: number[]): number;
export declare function subtract(xs1: any[], xs2: any[]): any[];
export declare function uniq(xs: any[]): any[];
export declare function unpickAll<T = any>(m: T, keys: any[]): Partial<T>;
export declare function isEmpty(xs: any): boolean;
export declare function distance(xy1: {
    x: number;
    y: number;
}, xy2: {
    x: number;
    y: number;
}): number;
export declare function coordinateTransform(x: number, y: number, dx: number, dy: number, dAngleDeg: number): {
    x: number;
    y: number;
};
export declare function round(x: number, f: number): number;