export declare class Preconditions {
    static assertCondition(assertion: boolean, message: string): void;
    static assert<T>(value: T, testFunction: AssertionFunction<T>, message: string): T;
    static assertEqual<T>(value: T, expected: T, name: string): T;
    static assertNumber(value: any, name: string): any;
    static assertInstanceOf(value: any, instance: any, name: string): any;
    static assertString(value: any, name: string): string;
    static assertTypeOf(value: any, type: string, name: string, handler?: () => void): any;
    static assertNotNull<T>(value: T | null, name?: string): NonNullable<T>;
    static assertPresent<T>(value: T | null, name?: string): NonNullable<T>;
    static assertAbsent<T>(value: T): void;
    static assertNotTypeOf<T>(value: any, name: string, type: string): T;
    static assertNotInstanceOf<T>(value: T, name: string, instance: any): T;
    static defaultValue<T>(value: T | undefined | null, defaultValue: T): NonNullable<T>;
    static isPresent(val: any): boolean;
}
export declare type AssertionFunction<T> = (val: T) => boolean;
export declare function defaultValue<T>(value: T | undefined | null, defaultValue: T): NonNullable<T>;
export declare function notNull<T>(value: T | null, name?: string): NonNullable<T>;
export declare function isPresent(val: any): boolean;
export declare function isPresent2<T>(val: T | null | undefined): val is Exclude<T, null | undefined>;