Mailspring plugin to assign a class to each thread list row

main.js

// keep in mind this is a plain JavaScript file - the app won't "transpile" it
// in any way (Mailspring used to run Babel when it read plugin source code,
// but it became difficult to package up Babel as part of the application).
// We can still use most ES2016 language features because we use the latest Chrome.

// When you add this file to your theme also be sure to add a `main` entry to the
// package.json file to tell it that it should load this as the entrypoint of your plugin:
//
// {
//   "main": "./main",
//   ...
// }

const { ExtensionRegistry, AccountStore } = require('mailspring-exports');

const ThemeThreadListExtension = {
  name: 'ThemeThreadListExtension',

  cssClassNamesForThreadListItem(thread) {
    const allAccountIds = AccountStore.accountIds();
    return `account-${allAccountIds.indexOf(thread.accountId)}`;
  },
  cssClassNamesForThreadListIcon(thread) {
    return '';
  },
};

module.exports = {
  activate() {
    ExtensionRegistry.ThreadList.register(ThemeThreadListExtension);
  },

  deactivate() {
    ExtensionRegistry.ThreadList.unregister(ThemeThreadListExtension);
  },
};