import type { PostHogConfig, Properties } from '@posthog/types';
export declare function find<T>(value: T[], predicate: (value: T) => boolean): T | undefined;
export declare function eachArray<E = any>(obj: E[] | null | undefined, iterator: (value: E, key: number) => void): void;
export declare function each(obj: any, iterator: (value: any, key: any) => void): void;
export declare const extend: (obj: Record<string, any>, ...args: Record<string, any>[]) => Record<string, any>;
/**
 * Object.entries() polyfill
 * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries
 */
export declare function entries<T = any>(obj: Record<string, T>): [string, T][];
export declare const trySafe: <T>(fn: () => T) => T | undefined;
export declare const safewrap: <F extends (...args: any[]) => any = (...args: any[]) => any>(f: F) => F;
export declare const safewrapClass: (klass: Function, functions: string[]) => void;
export declare const stripEmptyProperties: (p: Properties) => Properties;
export declare function _copyAndTruncateStrings<T extends Record<string, any> = Record<string, any>>(object: T, maxStringLength: number): T;
export declare function isCrossDomainCookie(documentLocation: Location | undefined): boolean;
export declare function addEventListener(element: Window | Document | Element | undefined, event: string, callback: EventListener, options?: AddEventListenerOptions): void;
/**
 * Helper to migrate deprecated config fields to new field names with appropriate warnings
 * @param config - The config object to check
 * @param newField - The new field name to use
 * @param oldField - The deprecated field name to check for
 * @param defaultValue - The default value if neither field is set
 * @param loggerInstance - Optional logger instance for deprecation warnings
 * @returns The value to use (new field takes precedence over old field)
 */
export declare function migrateConfigField<T>(config: Record<string, any>, newField: string, oldField: string, defaultValue: T, loggerInstance?: {
    warn: (message: string) => void;
}): T;
export declare function isToolbarInstance(config: Pick<PostHogConfig, 'name'>): boolean;