export declare function toFixedNumber(num: any, fractionDigits?: number): any;
export declare function decimalLength(value: number): number;
export declare function by(fn: (num: number) => number): (divisor: number, offset?: number) => (num: number) => any;
export declare const roundBy: (divisor: number, offset?: number) => (num: number) => any;
export declare const floorBy: (divisor: number, offset?: number) => (num: number) => any;
export declare const ceilBy: (divisor: number, offset?: number) => (num: number) => any;
/**
 * 把一个值限制在一个上限和下限之间
 * @param _num 当前数字
 * @param lower 最小值
 * @param upper 最大值
 */
export declare function clamp(_num: number, lower?: number, upper?: number): number;
export declare function mix(x: number, y: number, _a: number): number;