refacotr: memorize getState and applyMiddleware

[ariesjia]

No description provided.

[ariesjia]

related to #164

[wardoost]

It's unnecessary to memoize getState as state changes after every update. In this patch getState will always return the initial state which is not correct behaviour.

After removing the memoization I tried using this method of composing the middleware functions but it doesn't seem to work correctly. The addAndReset action use all middleware correctly. I don't fully understand why but reduxjs/redux#2145 is an interesting thread on this issue so I'll have a better look at that soon.

[ariesjia]

fixed getState always return the initial state issue , reducer will always return a new object , so we can memoize the getState method as state changes.

now the storybook demo works as previously

[wardoost]

While I see memoizing getState/middlewareAPI is needed when using this hook in combination with other hooks this branch also suffers from the issue mentioned in #164 (comment).