Portal activation data polyfill

portal-utils.js

const ACTIVATE_MESSAGE_PREFIX = "portal-activate-";

export function activateWithMessage(portal, messageType, messageData) {
  portal.activate();
  portal.postMessage({ type: ACTIVATE_MESSAGE_PREFIX + messageType, data: messageData });
}

export async function waitForActivateWithMessage() {
  const [{ messageType, messageData }, event] = await Promise.all([
    waitForActivateMessage(),
    waitForActivateEvent()
  ])
  
  return {
    event,
    messageType,
    messageData
  };
}

function waitForActivateMessage() {
  return new Promise(resolve => {
    window.addEventListener("message", e => {
      if (typeof e.data === "object" &&
          typeof e.data.type === "string" &&
          e.data.type.startsWith(ACTIVATE_MESSAGE_PREFIX)) {
        resolve({
          messageType: e.data.type.substring(ACTIVATE_MESSAGE_PREFIX.length),
          messageData: e.data.data
        });
      }
    });
  });
}

function waitForActivateEvent() {
  return new Promise(resolve => {
    window.addEventListener("portalactivate", resolve);
  });
}