It's been more than 5 years since I am taking interviews for front-end developers and gradually the trend is changing towards Frameworks/Libraries.
I am not against using any library or framework, I know it makes your development cycle faster and gives you some kind of pre-defined architecture where you can follow best practices but we shouldn't forget basics.
I would suggest directly starting with ES6 (ECMAScript) since the latest browsers support it and you can use a transcompiler like Babel if you need to support legacy browsers.
Organization's point of view
Client awareness: If your clients are coming with such asks to implement a new framework or library, it's a good opportunity to do quick requirements check instead of directly jumping on implementation.