Redux Toolkit is a powerful tool for managing application state in JavaScript applications. It simplifies the process of writing Redux code and makes it more efficient. One common use case for Redux Toolkit is constructing complex queries.

Why complex queries?

In many applications, we often need to fetch data from an API endpoint that requires complex filtering, sorting, or pagination. These queries can quickly become cumbersome to handle manually, especially as the complexity of the application grows.

Redux Toolkit provides a solution for managing complex queries in a more structured and organized manner.

The Query Builder pattern

One way to handle complex queries with Redux Toolkit is by using the Query Builder pattern. This pattern involves creating a separate slice of state dedicated to managing the query parameters and constructing the query string.

Here’s an example implementation using Redux Toolkit:

import { createSlice, createAsyncThunk } from '@reduxjs/toolkit';

const initialState = {
  filters: {},
  sortBy: '',
  pageNumber: 1,
};

const querySlice = createSlice({
  name: 'query',
  initialState,
  reducers: {
    setFilter: (state, action) => {
      const { name, value } = action.payload;
      state.filters[name] = value;
    },
    setSortBy: (state, action) => {
      state.sortBy = action.payload;
    },
    setPageNumber: (state, action) => {
      state.pageNumber = action.payload;
    },
  },
});

export const { setFilter, setSortBy, setPageNumber } = querySlice.actions;

export const fetchQueryData = createAsyncThunk(
  'query/fetchData',
  async (_, { getState }) => {
    const { filters, sortBy, pageNumber } = getState().query;
    // Construct the query string based on the state
    const queryString = `?filter=${filters}&sort=${sortBy}&page=${pageNumber}`;
    // Fetch data using the constructed query
    const response = await fetch(`/api/data${queryString}`);
    return response.json();
  }
);

export default querySlice.reducer;

In the above code, we define a query slice of state that holds the filter, sort by, and page number parameters. We also have corresponding actions to update these parameters.

The fetchQueryData async thunk is responsible for fetching the data using the constructed query string based on the current state. This thunk can be dispatched whenever the query parameters change, triggering the API call.

Conclusion

By using Redux Toolkit, we can effectively manage complex queries in a more structured and organized manner. The Query Builder pattern allows us to separate concerns and handle query construction and state management separately. This simplifies the process of managing complex queries and enhances the overall efficiency of our Redux code.

#redux #querybuilding