⚙️ Service Worker Internals

The background script in src/service-worker.ts acts as the event-driven coordinator for the entire extension lifecycle.

Responsibilities

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1. Context Menus Management

On chrome.runtime.onInstalled, the service worker sets up contextual items:

chrome.runtime.onInstalled.addListener(() => {
  chrome.contextMenus.create({
    id: 'hckr-root',
    title: 'hckr Dev Toolkit',
    contexts: ['selection']
  });

  chrome.contextMenus.create({
    parentId: 'hckr-root',
    id: 'hckr-json',
    title: 'Format as JSON',
    contexts: ['selection']
  });

  chrome.contextMenus.create({
    parentId: 'hckr-root',
    id: 'hckr-jwt',
    title: 'Decode JWT',
    contexts: ['selection']
  });

  chrome.contextMenus.create({
    parentId: 'hckr-root',
    id: 'hckr-base64',
    title: 'Base64 Decode',
    contexts: ['selection']
  });
});

When clicked, the payload is forwarded to the active tab's side panel via storage or runtime messaging.

---

2. Fast Tab Switching (Alt+Q)

Tracks the user's active tab transitions using a 2-element stack:

let activeTabId: number | null = null;
let previousTabId: number | null = null;

chrome.tabs.onActivated.addListener((activeInfo) => {
  if (activeTabId !== null && activeTabId !== activeInfo.tabId) {
    previousTabId = activeTabId;
  }
  activeTabId = activeInfo.tabId;
});

chrome.commands.onCommand.addListener(async (command) => {
  if (command === 'switch-to-previous-tab' && previousTabId !== null) {
    try {
      await chrome.tabs.update(previousTabId, { active: true });
    } catch {
      // Tab may have been closed
      previousTabId = null;
    }
  }
});

---

3. Side Panel Trigger

On clicking the extension toolbar icon (chrome.action.onClicked):

chrome.action.onClicked.addListener(async (tab) => {
  if (tab.id) {
    await chrome.sidePanel.open({ tabId: tab.id });
  }
});