import { type Readable } from 'svelte/store';
/**
 * The state of an A/B experiment for the current session.
 */
export type ExperimentState = {
    /**
     * The variant assigned to this session. Until assignment resolves (and on
     * the server, or when analytics is disabled), this is the first variant —
     * treat the first variant as the control.
     */
    variant: Readable<string>;
    /**
     * `true` once the variant has been deterministically assigned and its
     * exposure recorded. Useful to defer rendering when a flash of the control
     * variant is not acceptable.
     */
    isAssigned: Readable<boolean>;
};
/**
 * Assigns this session to a variant of an A/B experiment and records the
 * exposure, scoped to `experimentKey`, so the backend can compute per-variant
 * conversion rates against `useConversion` events.
 *
 * Assignment is deterministic per session (no server round-trip, stable across
 * re-mounts). The exposure is recorded once per mount.
 *
 * @param experimentKey - Unique key identifying the experiment.
 * @param variants - The candidate variant names; the first one is the control.
 * @param weights - Optional relative weights, one per variant (e.g. `[9, 1]`).
 * @returns The {@link ExperimentState} for this session.
 *
 * @example
 * ```svelte
 * <script>
 *   const { variant } = useExperiment('homepage-hero', ['a', 'b']);
 *   const content = useIntlayer($variant === 'b' ? 'hero-b' : 'hero');
 * </script>
 * ```
 */
export declare const useExperiment: (experimentKey: string, variants: string[], weights?: number[]) => ExperimentState;