context.ts

/*
 * Copyright (c) 2023, salesforce.com, inc.
 * All rights reserved.
 * SPDX-License-Identifier: MIT
 * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
 */

import { createContextProviderWithRegister } from '@lwc/engine-core';
import { addEventListener, dispatchEvent } from './index';
import type {
    WireAdapterConstructor,
    WireContextValue,
    WireContextSubscriptionPayload,
    WireContextSubscriptionCallback,
} from '@lwc/engine-core';

export class WireContextSubscriptionEvent extends CustomEvent<undefined> {
    // These are initialized on the constructor via defineProperties.
    public readonly setNewContext!: (newContext: WireContextValue) => boolean;
    public readonly setDisconnectedCallback?: (disconnectCallback: () => void) => void;

    constructor(
        adapterToken: string,
        { setNewContext, setDisconnectedCallback }: WireContextSubscriptionPayload
    ) {
        super(adapterToken, {
            bubbles: true,
            composed: true,
        });

        this.setNewContext = setNewContext;
        this.setDisconnectedCallback = setDisconnectedCallback;
    }
}

/**
 * Creates a context provider, given a wire adapter constructor.
 * @param adapter The wire adapter to create a context provider for.
 * @returns A new context provider.
 */
export function createContextProvider(adapter: WireAdapterConstructor) {
    return createContextProviderWithRegister(adapter, registerContextProvider);
}

export function registerContextConsumer(
    elm: Node,
    adapterContextToken: string,
    subscriptionPayload: WireContextSubscriptionPayload
) {
    dispatchEvent(elm, new WireContextSubscriptionEvent(adapterContextToken, subscriptionPayload));
}

export function registerContextProvider(
    elm: Node,
    adapterContextToken: string,
    onContextSubscription: WireContextSubscriptionCallback
) {
    addEventListener(elm, adapterContextToken, ((evt: WireContextSubscriptionEvent) => {
        const { setNewContext, setDisconnectedCallback } = evt;
        // If context subscription is successful, stop event propagation
        if (
            onContextSubscription({
                setNewContext,
                setDisconnectedCallback,
            })
        ) {
            evt.stopImmediatePropagation();
        }
    }) as EventListener);
}