background.js

// Copyright (c) 2019 SafetyCulture Pty Ltd. All Rights Reserved.

// Map of Panel connections. The 'tabId' is used as key.
// There are two connections/ports for every tabId
// 1) Port to the panel script
// 2) Port to the content script
//
// Example:
// connections[1].panel => pane port
// connections[1].content => content port

/* global chrome */

let connections = {};

// eslint-disable-next-line no-undef
chrome.runtime.onConnect.addListener(port => {
  if (port.name !== "panel" && port.name !== "content") {
    return;
  }

  let extensionListener = message => {
    const tabId = port.sender?.tab?.id >= 0 ? port.sender.tab.id : message.tabId;

    // The original connection event doesn't include the tab ID of the
    // DevTools page, so we need to send it explicitly (attached
    // to the 'init' event).
    if (message.action === "init") {
      if (!connections[tabId]) {
        connections[tabId] = {};
      }
      connections[tabId][port.name] = port;
      return;
    }

    // Other messages are relayed to specified target if any
    // and if the connection exists.
    if (message.target) {
      const conn = connections[tabId][message.target];
      if (conn) {
        conn.postMessage(message);
      }
    }
  };

  // Listen to messages sent from the panel script.
  port.onMessage.addListener(extensionListener);

  // Remove panel connection on disconnect.
  port.onDisconnect.addListener(function (port) {
    port.onMessage.removeListener(extensionListener);

    const tabs = Object.keys(connections);
    for (let i = 0, len = tabs.length; i < len; i++) {
      if (connections[tabs[i]][port.name] === port) {
        delete connections[tabs[i]][port.name];

        // If there is not port associated to the tab, remove it
        // from the connections map.
        if (Object.keys(connections[tabs[i]]).length === 0) {
          delete connections[tabs[i]];
        }
        break;
      }
    }
  });
});