import type { ApolloClient, TypePolicies } from '@apollo/client';
import type { ApolloController } from '@apollo-elements/core';
declare global {
    interface HTMLElementTagNameMap {
        'apollo-client': ApolloClientElement;
    }
}
/**
 * Provides an ApolloClient instance to all nested ApolloElement children,
 * even across (open) shadow boundaries.
 *
 * @element apollo-client
 *
 * @fires {CustomEvent<{ client: ApolloClient}> client-changed - The client changed
 *
 * @example <caption>Generate a simple ApolloClient instance</caption>
 * ```html
 *          <apollo-client uri="/graphql"></apollo-client>
 * ```
 *
 * @example <caption>Prevent network calls when required variables are absent</caption>
 * ```html
 *          <apollo-client uri="/graphql" validate-variables></apollo-client>
 * ```
 *
 * @example <caption>Providing a client to a tree of Nodes</caption>
 * ```html
 *          <apollo-client id="client-a">
 *            <apollo-mutation>
 *              <!--...-->
 *            </apollo-mutation>
 *          </apollo-client>
 * ```
 *
 * @example <caption>Nesting separate clients</caption>
 * ```html
 *          <apollo-client id="client-a">
 *            <query-element>
 *              <!-- This element queries from client-a's endpoint -->
 *            </query-element>
 *            <apollo-client id="client-b">
 *              <query-element>
 *                <!-- This element queries from client-b's endpoint -->
 *              </query-element>
 *            </apollo-client>
 *          </apollo-client>
 * ```
 */
export declare class ApolloClientElement extends HTMLElement {
    #private;
    static readonly is: "apollo-client";
    static readonly observedAttributes: string[];
    /**
     * @summary Reference to the `ApolloClient` instance.
     *
     * Set the `client` property to update all of this element's deep children.
     */
    get client(): ApolloClient | null;
    set client(client: ApolloClient | null);
    /** @summary List of all Apollo Controllers registered to this client. */
    get controllers(): readonly (ApolloController)[];
    /**
     * @summary Type Policies for the client.
     *
     * Set this property with a `TypePolicies` object to add them to the cache.
     */
    get typePolicies(): TypePolicies | undefined;
    set typePolicies(typePolicies: TypePolicies | undefined);
    /**
     * When the URI attribute is set, `<apollo-client>` will asynchronously
     * create a new ApolloClient instance with some default parameters
     *
     * @summary URI to the GraphQL server.
     * @attr uri
     */
    get uri(): string | undefined;
    set uri(uri: string | undefined);
    /**
     * When true, client will not fetch operations that do not have all their non-nullable variables set.
     *
     * @summary Whether to try to validate operations
     * @attr validate-variables
     */
    get validateVariables(): boolean;
    set validateVariables(v: boolean);
    constructor();
    attributeChangedCallback(attr: string, oldValue: string, newValue: string): void;
    connectedCallback(): void;
    /**
     * @summary Creates an Apollo client and assigns it to child elements
     * @return An `ApolloClient` instance.
     */
    createApolloClient(): Promise<ApolloClient>;
    private findDeepInstances;
    private addDeepInstance;
    /**
     * Assigns the element controller's client instance to the child,
     * and registers the child to receive the element's new client when its set.
     */
    private onElementConnected;
    /**
     * Performs clean up when the child disconnects
     */
    private onElementDisconnected;
    /**
     * Set the client on the element's controller,
     * and if it's a query or subscription controller, attempt to subscribe
     */
    private initialize;
}