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react-dnd can interface with a couple of different drag-n-drop api's. This is needed for the difference between using a laptop and using a touch device (like a phone or tablet). This particular backend is for laptops/desktops, and should not be expected to work reliably with touch devices. If we want to include support for that, this backend can be substituted for a different appropriate backend that supports touch.

Middleware

redux-

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redux-promise intercepts dispatched actions with a key "payload" and value set to a Promise. All it does is wait for the Promise to resolve itself before allowing the action to proceed onto the reducers.

redux-saga

redux-saga allows complex, async dispatches. It can be used to intercept actions before they hit reducers, perform async actions, and dispatch even more actions depending on the results.

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