Library based on the FLUX architecture, often used with React. Flux (stream, flow) is a design pattern proposed by Facebook. Information in FLUX flows in only one direction which is always the same (unidirectional data flow). Redux is an implementation of the Flux architecture, to which some functional programming has been added and the Event Sourcing pattern was used - Event Sourcing's task is to restore the current state of the application based on the events stored in the data store. In short, Redux allows you to store your data in a global object that can be referenced anywhere in your application.

Redux assumptions:

1. Single source of truth (The entire state of the application is stored in a tree in one data store).
2. The state is read only. (All changes are made through actions).
3. Changes are made with pure functions. To define how an action affects state, a reducer should be written, which is pure function – something that does not try to change arguments and always returns the same result for the same arguments.

Redux is a very important library that allows you to design an application in a better and more flexible way, as it allows you to store and manage the state of the entire application. Many libraries have been created for Redux, such as Redux Logger (which facilitates debugging the application state), Redux Persist (which additionally saves the application state in the browser's data store) and Redux-Saga, which is used to handle asynchronous application functions.

Redux Homepage