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Odonno / ReduxSimple

Simple Stupid Redux Store using Reactive Extensions
http://www.nuget.org/packages/ReduxSimple/
MIT License
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Display warning when a `null` action is dispatched (only in DEBUG) #10

Closed Odonno closed 5 years ago

Odonno commented 6 years ago

Until C# forbid nullable variables/parameters (in C# 8 I think), how do we deal with null action?

mhusainisurge commented 6 years ago

I think we can allow it and let the Reduce implementation handle that case.

quetzalcoatl commented 5 years ago

My (initial) view on that point is exactly the same as mhusainisurge's: why interfere at all?

If you can allow to pass a new object() as an action and have the reducers handle it, then null, DBNull.Value, 1, etc. should be treated just the same. That's what a developer with some experience in redux would expect.

However, I can see a problem for new developers who struggle with their jobs. Any NullReferenceException is a problem, many find it hard to trace where the null come from.. Now in redux scheme, where you dispatch actions -anywhere- and they just show up in reducers, a null-action can easily cause a NRE in poorly-written reducers, and then finding the source of that action is something I believe many may have problems with.

So.. I change my opinion:

Although my first reaction was "why interfere? let it pass", and even now I still feel that's the right way to do from the point of view of "redux theory", I suppose that the best way to handle null actions is ... to ignore them.

Conceptually, a null is nothing, or a "dont know" value, and an action sent to the store should define what to do. A Store receiving null as action may either pass them to reducers and risk a NRE which may cause a developer some pain, or it can play along the 'nothing' concept and do nothing. No reducer fired, no state change, no store update. A nice thing would be to issue a trace-warning about a null-action received could be issued, as sending a null instead of an action is not a normal thing, but only in DEBUG builds.

Odonno commented 5 years ago

Hi @quetzalcoatl

First of all, thanks for the point of view.

My first question is "should we wait for C#8 which will handle null with ease or should we filter this value now?". Given your point of view, I get to the conclusion that we should ask this underlying question: "did you ever experience a null action and in what context?".

Odonno commented 5 years ago

@quetzalcoatl I just re-read your post today. Seems I missed the part about a warning in debug mode when the action dispatched is null. Seems fair and easy to add. I'll add it to my todo list for the 2.1 version.

Odonno commented 5 years ago

This is now added in the version 2.1 of ReduxSimple.

https://www.nuget.org/packages/ReduxSimple/2.1.0