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import compose from './compose'
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/**
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* Creates a store enhancer that applies middleware to the dispatch method
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* of the Redux store. This is handy for a variety of tasks, such as expressing
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* asynchronous actions in a concise manner, or logging every action payload.
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*
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* See `redux-thunk` package as an example of the Redux middleware.
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*
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* Because middleware is potentially asynchronous, this should be the first
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* store enhancer in the composition chain.
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*
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* Note that each middleware will be given the `dispatch` and `getState` functions
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* as named arguments.
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*
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* @param {...Function} middlewares The middleware chain to be applied.
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* @returns {Function} A store enhancer applying the middleware.
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*/
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export default function applyMiddleware(...middlewares) {
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return createStore => (...args) => {
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const store = createStore(...args)
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let dispatch = () => {
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throw new Error(
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'Dispatching while constructing your middleware is not allowed. ' +
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'Other middleware would not be applied to this dispatch.'
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)
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}
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const middlewareAPI = {
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getState: store.getState,
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dispatch: (...args) => dispatch(...args)
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}
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const chain = middlewares.map(middleware => middleware(middlewareAPI))
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dispatch = compose(...chain)(store.dispatch)
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return {
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...store,
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dispatch
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}
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}
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}
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