Which is why a lot of people that encourage Redux tend to also encourage one or more of the "side effect" managers such as thunks, sagas, or observables (my preference).
From my perspective, React is the thing with the problem: it doesn't have great state management for complex tasks / multi-component coordination. What I want to use is something like RxJS to manage such interactions and state, because it gives me a lot of power/control in a relatively easy way. One of the best options out there that I've seen is redux-observable, and thus Redux itself is just the "stuff inside the oreo" gluing React to all my interesting "epics" describing high level functionality in the applications.
It's also the Unix philosophy thing of use tools that "do one thing well" and then chain them together. React does view components rather well, Redux does state management rather well, Redux-Observable does state "interaction" rather well. Chained together they work remarkably well.
I liked it more than redux, because you can have have simple class implementation and side effects without much hassle. Also TS support and testing is easy.
The observer pattern is mentioned in the Gang of Four Book[1], published in 1994. JavaScript first appeared in 1995. Observers predate Redux. You don't need Redux to use observers, and in fact there's nothing about React that is incompatible with RxJS.
> It's also the Unix philosophy thing of use tools that "do one thing well" and then chain them together. React does view components rather well, Redux does state management rather well, Redux-Observable does state "interaction" rather well. Chained together they work remarkably well.
Don't sully UNIX philosophy by comparing it to Redux! UNIX is such a different environment from JS space that it's hard to really even compare the two, but at the very least I think we can agree that "Doing one thing well" in UNIX means not creating a bunch of new problems that you need other tools to solve.
[1] https://www.amazon.com/Design-Patterns-Object-Oriented-Addis...
When I hear someone complaining about redux using global state, I like to ask them what makes global state bad. The answer is usually that it allows any part of the application to change a value, which makes debugging difficult. This doesn't apply to redux and similar frameworks because every slice of the state can only be managed by a single, pure function, which makes it incredibly easy to debug. Additionally, redux uses a copy on write mechanism, so your state tree isn't actually being mutated, which allows you to use equality comparison instead of a deep compare to see what state has changed. That, combined with the fact that all actions go through a central dispatcher that is easily audited means unit testing your state transitions is almost laughably trivial. And since you are pulling all of your business logic out of your UI components, you can avoid the side-effect hell of unit testing your UI.
Having said that, I won't use react or redux for any website that doesn't have a heavily interactive UI with complex state that must be shared across many pages. Managing application state in your front end is an enormous burden and you'd be crazy to take it on without a need for it.
I respectfully disagree here. All UI views in React can be controlled via parameters. Very few components in a React application require state management. You can add parameter functions to handle various events as well.
> which allows you to use equality comparison instead of a deep compare to see what state has changed
You are doing a lot of deep compares on state in a real world application? Why? If you only use parameters for the state of your component, everything is already handled by React out of the box.
> every slice of the state can only be managed by a single, pure function
Really? You can trigger reducers from literally anywhere in your application. Not only that, you can create multiple reducers to handle each action type. I've seen a situation with 24(yup, 24) reducer functions for a single action type. Many of those reducers contained complex business logic checking the overall state of the application. Then you have 2 or 3 action functions all with different business logic for that one type. Race conditions everywhere. setTimeout 0, here we go again. Step debugger hell. Of course, you should never do this, but in the real world, this is what happens over and over again.
> means unit testing your state transitions is almost laughably trivial
If you use parameters for state of a component it is 1,000 times easier. Because a component's view is not coupled to the global state of your application. Pass it parameters, test that it looks correct. Change a parameter, check if it is correct. Dead simple. Your tests are not bound to global state at all. Again, you started with an anti-pattern of managing state in child components, and now, instead of not doing the anti-pattern, you are adding yet another tool to fix it. Instead of just not doing it.
In summary, what you are describing is the "theory" of why Redux and associated tools should work. In every case that I've seen(10+ at this point) that has not happened. Not because Redux is a bad tool. Its not. But in the real world, it has become incredibly expensive for many organizations to maintain.
