With a browser? Absolutely, though you need to explicitly use to the commonjs build of ably-js -- see instructions at https://github.com/ably/ably-js/#using-webpack .
In node.js? Unfortunately currently not; you'll need to exclude ably from webpack bundling (using `externals` in the webpack config), and require and use it in as a external module, using require('ably'). If that is an issue for you, please contact us and we'll try and find you a solution.