WebExtension permission cache

permission-cache.mjs

export class PermissionCache {
  static areas = ["origins", "permissions", "data_collection"];

  origins = [];
  permissions = [];
  data_collection = [];
  ready;

  constructor () {
    this.ready = browser.permissions.getAll().then((grants) => {
      this.handleAdded(grants);
      return this;
    });

    browser.permissions.onAdded.addListener(this.handleAdded);
    browser.permissions.onRemoved.addListener(this.handleRemoved);
  }

  handleAdded(added) {
    for (const key of PermissionCache.areas) {
      const addedValues =  added[key] || [];
      this[key].push(...addedValues);
    }
  }
  handleAdded = Object.getPrototypeOf(this).handleAdded.bind(this);

  handleRemoved(removed) {
    for (const key of PermissionCache.areas) {
      const currentValues = this[key] || [];
      const removedValues = removed[key] || [];
      for (const removedVal of removedValues) {
        const index = currentValues.indexOf(removedVal);
        if (index !== -1) currentValues.splice(index, 1);
      }
    }
  }
  handleRemoved = Object.getPrototypeOf(this).handleRemoved.bind(this);
};

// Example usage
const perms = new PermissionCache();

browser.action.onClicked.addListener(async () => {
  if (!perms.isReady) await perms.ready;

  if (perms.data_collection.includes("browsingData")) {
    
  } else {
    showBrowsingDataPrompt();
  }
});