import type { CacheableItemInterface } from '../types/index.js';
import type { CacheabilityInterface } from './CacheabilityInterface.js';
import { type MaxAge } from './maxAge.js';
type NumericKeys<T> = {
    [K in keyof T]: T[K] extends number | null ? K : never;
}[keyof T];
export declare class CacheHelper implements CacheabilityInterface {
    private readonly now;
    /**
     * The collected cache tags.
     */
    tags: string[];
    /**
     * Indicates if it should be cacheable.
     */
    cacheable: boolean | null;
    /**
     * The maximum age.
     */
    maxAge: number;
    /**
     * The stale if error age.
     */
    staleIfError: number | null;
    constructor(now: number);
    /**
     * Set a numeric property, but **only** when the new value is
     * lower than the existing one (or the property is still `null`).
     *
     * `property` is restricted to *numeric* properties of **whatever
     * concrete class `this` is*.  That includes fields that subclasses
     * add later.
     */
    setNumeric<K extends NumericKeys<this>>(property: K, providedValue: MaxAge): this;
    /**
     * Set the max age in seconds.
     *
     * The value is only set if it's smaller than the current max age or if it
     * hasn't been set yet. The initial value is `null`.
     *
     * You can always directly set the maxAge property on this object.
     */
    setMaxAge(v: MaxAge): this;
    /**
     * Set the staleIfError in seconds.
     *
     * If set, then a stale version of the component may be returned if an error happens during rendering.
     */
    setStaleIfError(v: MaxAge): this;
    /**
     * Add cache tags for this route.
     */
    addTags(tags?: string[] | string): this;
    /**
     * Mark this item as cacheable.
     *
     * The initial value is null and this method only changes the value if it is
     * null. This means that once it's set to uncacheable, there is no way to
     * change it back.
     */
    setCacheable(): this;
    /**
     * Mark the item as uncacheable.
     *
     * After that there is no way to make it cacheable again.
     */
    setUncacheable(): this;
    /**
     * Get the expire timestamp as unix epoch (seconds).
     */
    getExpires<K extends NumericKeys<this>>(property: K): number | undefined;
    /**
     * Whether the item is cacheable.
     */
    isCacheable(): boolean;
    mergeFromCacheItem(item: CacheableItemInterface): this;
    getMaxAge(): number;
    getStaleIfError(): number | null;
    getTags(): string[];
    mergeFromCacheability(cacheability: CacheabilityInterface): this;
}
export {};