bannerbanner/src

/* Show a page action button on a tab whenever the given predicate is true.
 * The predicate is passed a Tab object, and is evaluated whenever the tab has
 * changed.
 *
 * Example usage:
 *   pageAction({ predicate: tab => tab.url.startsWith('https') })
 */

import browser from 'webextension-polyfill'


export default async function pageActionButton({ predicate }) {
  async function maybeShowButton(tab) {
    if (await predicate(tab)) {
      browser.pageAction.show(tab.id)
    } else {
      browser.pageAction.hide(tab.id)
    }
  }

  // Show/hide the button on current tabs.
  const tabs = await browser.tabs.query({})
  for (const tab of tabs) {
    maybeShowButton(tab)
  }

  // Show/hide the button whenever a tab changes.
  browser.tabs.onUpdated.addListener((id, changeInfo, tab) => {
    maybeShowButton(tab)
  });
}