import { Signal } from "@preact-signals/unified-signals";
/**
 * Always return false.
 */
export declare const NO: () => boolean;
export declare const isOn: (key: string) => boolean;
export declare const isModelListener: (key: string) => boolean;
export declare const extend: {
    <T extends {}, U>(target: T, source: U): T & U;
    <T_1 extends {}, U_1, V>(target: T_1, source1: U_1, source2: V): T_1 & U_1 & V;
    <T_2 extends {}, U_2, V_1, W>(target: T_2, source1: U_2, source2: V_1, source3: W): T_2 & U_2 & V_1 & W;
    (target: object, ...sources: any[]): any;
};
export declare const remove: <T>(arr: T[], el: T) => void;
export declare const hasChanged: (value: any, oldValue: any) => boolean;
export declare const hasOwn: (val: object, key: string | symbol) => key is never;
export declare const isArray: (arg: any) => arg is any[];
export declare const isMap: (val: unknown) => val is Map<any, any>;
export declare const isSet: (val: unknown) => val is Set<any>;
export declare const isDate: (val: unknown) => val is Date;
export declare const isRegExp: (val: unknown) => val is RegExp;
export declare const isFunction: (val: unknown) => val is Function;
export declare const isString: (val: unknown) => val is string;
export declare const isSymbol: (val: unknown) => val is symbol;
export declare const isObject: (val: unknown) => val is Record<any, any>;
export declare const isPromise: <T = any>(val: unknown) => val is Promise<T>;
/**
 * Make a map and return a function for checking if a key
 * is in that map.
 * IMPORTANT: all calls of this function must be prefixed with
 * \/\*#\_\_PURE\_\_\*\/
 * So that rollup can tree-shake them if necessary.
 */
export declare function makeMap(str: string, expectsLowerCase?: boolean): (key: string) => boolean;
export declare const objectToString: () => string;
export declare const toTypeString: (value: unknown) => string;
export declare const toRawType: (value: unknown) => string;
export declare const isPlainObject: (val: unknown) => val is object;
export declare const isIntegerKey: (key: unknown) => boolean;
/**
 * @private
 */
export declare const capitalize: <T extends string>(str: T) => Capitalize<T>;
export declare const def: (obj: object, key: string | symbol, value: any) => void;
export declare const isSignal: (val: unknown) => val is Signal<any>;