Support supabase v2 refresh token logic for browser extensions

auth.ts

const EXPIRY_MARGIN = 10 * 1000;

class Auth {
  initialize = async () => {
    // Get the latest session, token may be refreshed
    const { data, error } = await supabase.auth.getSession();
    if (error) throw error;

    if (data.session?.expires_at) {
      // Create an alarm 10 seconds before token expiring
      browser.alarms.create('token-expired', {
        when: data.session.expires_at * 1000 - EXPIRY_MARGIN,
      });
    }
  };

  refreshToken = async () => {
    // Wrap in network retry timeout similar to https://github.com/supabase/gotrue-js/blob/master/src/GoTrueClient.ts#L761-L770
    await this._callRefreshToken();
  };

  private _callRefreshToken = async () => {
    const { data, error } = await supabase.auth.getSession();
    if (error) throw error;

    if (data.session) {
      const { data: newSessionData, error: newSessionError } = await supabase.auth.setSession(data.session.refresh_token);
      if (newSessionError) throw newSessionError;

      if (newSessionData.session?.expires_at) {
        // Create a new alarm for the next token expiration
        browser.alarms.create('token-expired', {
          when: newSessionData.session.expires_at * 1000 - EXPIRY_MARGIN,
        });
      }
    }
  };
}

export default new Auth();

background.ts

browser.alarms.onAlarm.addListener(async (alarm) => {
    if (alarm.name === 'token-expired) {
        await Auth.refreshToken();
        return;
    }
});

// Call in your initialization logic
Auth.initialize();

supabase.ts

import { createClient, SupportedStorage } from '@supabase/supabase-js';
import { browser } from 'webextension-polyfill-ts';

const supabaseUrl = process.env.SUPABASE_URL as string;
const supabaseKey = process.env.SUPABASE_PUBLIC_KEY as string;

const browserStorageInterface: SupportedStorage = {
  async getItem(key: string): Promise<string | null> {
    const storage = await browser.storage.local.get(key);
    return storage?.[key];
  },
  async setItem(key: string, value: string): Promise<void> {
    await browser.storage.local.set({
      [key]: value,
    });
  },
  async removeItem(key: string): Promise<void> {
    await browser.storage.local.remove(key);
  },
};

const supabase = createClient(supabaseUrl, supabaseKey, {
  auth: {
    persistSession: true,
    // This configuration is important, since now the extension is reponsible for refreshing the token
    autoRefreshToken: false,
    detectSessionInUrl: false,
    storage: browserStorageInterface,
  },
});

export default supabase;