penpal/lib/parent/handleAckMessageFactory.js

A promise-based library for communicating with iframes via postMessage.

import connectCallReceiver from '../connectCallReceiver';
import connectCallSender from '../connectCallSender';
/**
 * Handles an ACK handshake message.
 */
export default (serializedMethods, childOrigin, originForSending, destructor, log) => {
    const { destroy, onDestroy } = destructor;
    let destroyCallReceiver;
    let receiverMethodNames;
    // We resolve the promise with the call sender. If the child reconnects
    // (for example, after refreshing or navigating to another page that
    // uses Penpal, we'll update the call sender with methods that match the
    // latest provided by the child.
    const callSender = {};
    return (event) => {
        if (childOrigin !== '*' && event.origin !== childOrigin) {
            log(`Parent: Handshake - Received ACK message from origin ${event.origin} which did not match expected origin ${childOrigin}`);
            return;
        }
        log('Parent: Handshake - Received ACK');
        const info = {
            localName: 'Parent',
            local: window,
            remote: event.source,
            originForSending: originForSending,
            originForReceiving: childOrigin,
        };
        // If the child reconnected, we need to destroy the prior call receiver
        // before setting up a new one.
        if (destroyCallReceiver) {
            destroyCallReceiver();
        }
        destroyCallReceiver = connectCallReceiver(info, serializedMethods, log);
        onDestroy(destroyCallReceiver);
        // If the child reconnected, we need to remove the methods from the
        // previous call receiver off the sender.
        if (receiverMethodNames) {
            receiverMethodNames.forEach((receiverMethodName) => {
                delete callSender[receiverMethodName];
            });
        }
        receiverMethodNames = event.data.methodNames;
        const destroyCallSender = connectCallSender(callSender, info, receiverMethodNames, destroy, log);
        onDestroy(destroyCallSender);
        return callSender;
    };
};