Speacking of Flux/Redux: Flux is a concept how to handle data across components and how to store them, since at least in React it is not directly specified; it just handles the front end. You can pass data to your child components and that's it and in complex application you end up passing data across multiple layers of components.
And with Flux/Redux now you don't have to pass data across multiple layers of components, since they can pull it off the store itself. That's makes the components much smaller and cleaner, they don't have to pass data only for passing and do nothing more of with it.
That's kind of TLDR but that's how it's started. And now Redux is Framework agnostic, so you can use it with other Frameworks and apply the (unidirectional) data flow to it, despite of the may existing features.
I used it with angularJS (kind of bulky) and with vuex there is also a vue.js implementation.