Redux (JavaScript library)

Redux is an open-source JavaScript library for managing application state. It is most commonly used with libraries such as React or Angular for building user interfaces. Similar to (and inspired by) Facebook's Flux architecture, it was created by Dan Abramov and Andrew Clark.

Description
Redux is a small library with a simple, limited API designed to be a predictable container for application state. It operates in a similar fashion to a reducing function, a functional programming concept.

It is influenced by the functional programming language Elm.

History
Redux was created by Dan Abramov and Andrew Clark in 2015. Abramov began writing the first Redux implementation while preparing for a conference talk at React Europe on hot reloading. Abramov remarks, "I was trying to make a proof of concept of Flux where I could change the logic. And it would let me time travel. And it would let me reapply the future actions on the code change."

Abramov was struck by the similarity of the Flux pattern with a reducing function. "I was thinking about Flux as a reduce operation over time... your stores, they accumulate state in response to these actions. I was thinking of taking this further. What if your Flux store was not a store but a reducer function?"

Abramov reached out to Andrew Clark (author of the Flux implementation Flummox) as a collaborator. Among other things, he credits Clark with making the Redux ecosystem of tools possible, helping to come up with a coherent API, implementing extension points such as middleware and store enhancers.

In February 2019, useReducer was introduced as a React hook in the 16.8 release. It provides an API that is consistent with Redux, enabling developers to create Redux-like stores that are local to component states.