import { cond } from './index';
/**
 * Class of static boolean functions for finding whether a value is NOT an
 * empty instance of a type.
 */
export declare class notEmpty {
    static arr: (x: any) => boolean;
    static obj: (x: any) => boolean;
    static str: (x: any) => boolean;
    static map: (x: any) => boolean;
}
/**
 * Class of static boolean functions for finding whether a value is an empty
 * instance of a type.
 */
export declare class isEmpty {
    static arr: (x: any) => boolean;
    static obj: (x: any) => boolean;
    static str: (x: any) => boolean;
    static map: (x: any) => boolean;
}
/**
 * Class of static boolean functions for determining types and non-canonical
 * subtypes in JavaScript, such as natural or signable numbers.
 */
export declare class isType {
    /** All numbers except for `NaN` and `Infinity`. */
    static num: (x: any) => boolean;
    /** Checks if natural number, including zero. */
    static nat: (x: any) => boolean;
    static int: (number: number) => boolean;
    static str: (x: any) => boolean;
    /** Check if function. */
    static fn: (x: any) => boolean;
    /** Any signable number including `0` and `Infinity`, but excluding `NaN`. */
    static signable: (x: any) => boolean;
    static err: (x: any) => boolean;
    /** Checks if value is negative, but excludes `0` and `Infinity`. */
    static neg: (x: any) => boolean;
    static map: (x: any) => boolean;
}
/**
 * Returns the type of an unknown value as a lower-cased string. Type 'number'
 * is differentiated from 'nan' and 'infinity' because most numerical functions
 * don't expect them.
 *
 * @example
 * typeName(new Map)  // => 'map'
 * typeName(null)     // => 'null'
 * typeName([])       // => 'array'
 * typeName({})       // => 'object'
 * typeName(/\s+/)    // => 'regexp'
 * typeName(NaN)      // => 'nan'
 * typeName(-1/0)     // => 'infinity'
 */
export declare function typeName(x: any): string;
export declare const assert: (item: any, tests: cond[], callback?: Function) => void;