Data Normalization Middleware in Redux v5.0.0

Demonstrate a middleware that normalizes API response data before it reaches the action reducers in Redux v5.0.0.
const dataNormalizationMiddleware = store => next => action => {
    if (action.payload && action.meta && action.meta.normalize) {
        // Normalize the data here according to the schema defined in the action.meta
        const normalizedData = normalizeData(action.payload, action.meta.schema);
        // Create a new action with the same type but with normalized data
        const newAction = { ...action, payload: normalizedData };
        return next(newAction);
    return next(action);

function normalizeData(data, schema) {
    // Implement your normalization logic here based on the schema
    // For example, convert arrays of items to objects with IDs as keys,
    // or flatten nested structures as needed
    // This is a placeholder and should be replaced with actual implementation
    return data;
This JavaScript code snippet defines a data normalization middleware for Redux. It checks if the action has a payload and a normalization schema included in its metadata. If so, it normalizes the data using a 'normalizeData' function (which would need to be implemented based on the specific normalization requirements) and then creates a new action with the normalized data before passing it on to the next middleware or to the reducers.
const rootReducer = combineReducers({
    // ... your other reducers here ...

const store = createStore(
    // ... possibly other middlewares ...
This JavaScript code snippet demonstrates how to apply the 'dataNormalizationMiddleware' to the Redux store. It first combines the reducers into a 'rootReducer' and then creates the Redux store with the 'createStore' function, applying the middleware using the 'applyMiddleware' function. You would include other middlewares as needed.
const myApiDataAction = {
    payload: apiResponseData,
    meta: {
        normalize: true,
        schema: {
            // Define the normalization schema here
            // For example, an expected object structure, IDs, etc.
// Dispatch the action as usual
This JavaScript code snippet shows how to dispatch an action with normalization metadata. The action includes a 'type', a 'payload' containing the API response data, and a 'meta' field with a flag to indicate that the data should be normalized and a definition of the normalization schema. The 'store.dispatch' method is used to send this action through the Redux pipeline.
/* CSS styles are not included as they are not relevant to the implementation of data normalization middleware in Redux. */
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HTML structure is not necessary for the data normalization middleware in Redux, hence no HTML code is included.