/**
 * createStepper - the HEADLESS core behind <SvStepper>: per-step status
 * (complete / active / upcoming), the linear-vs-free clickability rule, and
 * navigation, as pure getters + prop-getters. No runes, framework-free, directly
 * unit-testable.
 *
 * ```svelte
 * <script lang="ts">
 *   import { createStepper } from '@svgrid/grid'
 *   const st = createStepper({ count: () => steps.length, current: () => i, onChange: (n) => (i = n) })
 * </script>
 * <ol>
 *   {#each steps as step, idx}
 *     <li class="is-{st.statusOf(idx)}">
 *       <button {...st.stepButtonProps(idx)}>{step.label}</button>
 *     </li>
 *   {/each}
 * </ol>
 * ```
 */
export type StepStatus = 'complete' | 'active' | 'upcoming';
export type StepperConfig = {
    count: () => number;
    /** 0-based index of the active step. */
    current: () => number;
    onChange?: (index: number) => void;
    /** Only allow navigating to already-reached steps. Default true. */
    linear?: () => boolean;
};
export declare function createStepper(config: StepperConfig): {
    statusOf: (i: number) => StepStatus;
    clickable: (i: number) => boolean;
    go: (i: number) => void;
    next: () => void;
    prev: () => void;
    isActive: (i: number) => boolean;
    /** Spread onto a step's button. */
    stepButtonProps: (i: number) => {
        'aria-current': "step" | undefined;
        disabled: boolean;
        onclick: () => void;
    };
};
export type Stepper = ReturnType<typeof createStepper>;