Redux Catch Promise orchestrating async actions

Redux Catch Promise: Orchestrating Async Actions in React Symphony

The Gray Cat
The Gray Cat

Redux Catch Promise is an extended replacement for the popular redux-thunk middleware, designed to supercharge your React applications with enhanced asynchronous action handling and server-side rendering capabilities. This powerful tool allows developers to write action creators that return functions instead of plain action objects, enabling complex asynchronous operations and conditional dispatching.

Composing Your Async Symphony

At its core, redux-catch-promise builds upon the concept of thunks - functions that wrap expressions to delay their evaluation. This approach opens up a world of possibilities for managing side effects and asynchronous logic in your Redux applications.

Key Features

  • Async/Await Support: Seamlessly work with modern JavaScript’s async/await syntax.
  • Server-Side Rendering: Implement server-side rendering for React components with asynchronous state.
  • Promise Catching: Easily handle and track dispatched promises and async functions.
  • Flexible Action Creators: Write action creators that can decide when and what to dispatch based on application state.

Installing the Middleware

To begin your journey with redux-catch-promise, you’ll need to install it in your project. You can do this using npm or yarn:

npm install redux-catch-promise --save
# or
yarn add redux-catch-promise

Basic Usage: Crafting Your First Async Action

Let’s dive into how you can use redux-catch-promise to create asynchronous actions. Here’s a simple example:

import { Dispatch } from 'redux';

const SHOW_USER_LOCATION = 'SHOW_USER_LOCATION';

interface UserLocation {
  location: string;
}

function showUserLocation(location: string): UserLocation {
  return {
    type: SHOW_USER_LOCATION,
    location
  };
}

function requestUserLocation(userName: string) {
  return async (dispatch: Dispatch) => {
    try {
      const response = await fetch(`https://api.github.com/users/${userName}`);
      const data = await response.json();
      dispatch(showUserLocation(data.location));
    } catch (error) {
      console.error('Error fetching user location:', error);
    }
  };
}

In this example, requestUserLocation is an action creator that returns an async function. This function performs an API call to fetch a user’s location and then dispatches the showUserLocation action with the retrieved data.

Advanced Techniques: Orchestrating Complex Async Flows

Catching Dispatched Promises

Redux Catch Promise allows you to track and manage dispatched promises, which is particularly useful for coordinating complex asynchronous flows:

import { createStore, applyMiddleware, combineReducers } from 'redux';
import CatchPromise from 'redux-catch-promise';
import * as reducers from './reducers';

const reducer = combineReducers(reducers);

const actionPromises: Promise<any>[] = [];
const createStoreWithMiddleware = applyMiddleware(
  CatchPromise((promisedAction, action, store) => {
    actionPromises.push(promisedAction);
  })
)(createStore);

const store = createStoreWithMiddleware(reducer);

This setup allows you to keep track of all dispatched promises, enabling you to wait for all asynchronous actions to complete before rendering or performing other operations.

Server-Side Rendering with Async State

One of the most powerful features of redux-catch-promise is its ability to facilitate server-side rendering with asynchronous state. Here’s a simplified example of how you might implement this:

import React from 'react';
import { renderToString } from 'react-dom/server';
import { createStore, applyMiddleware } from 'redux';
import CatchPromise from 'redux-catch-promise';
import App from './App';

export async function renderApp(req: any, res: any) {
  const preparePromises: Promise<any>[] = [];
  const serverSideRendering = {
    preparePromises,
    sharedState: {}
  };

  const store = createStore(
    rootReducer,
    applyMiddleware(CatchPromise((promisedAction) => {
      preparePromises.push(promisedAction);
    }))
  );

  const app = (
    <App store={store} serverSideRendering={serverSideRendering} />
  );

  let content = renderToString(app);

  if (preparePromises.length > 0) {
    await Promise.all(preparePromises);
    content = renderToString(app);
  }

  const finalState = store.getState();

  res.send(`
    <!DOCTYPE html>
    <html>
      <head>
        <title>My SSR App</title>
      </head>
      <body>
        <div id="root">${content}</div>
        <script>
          window.__PRELOADED_STATE__ = ${JSON.stringify(finalState).replace(/</g, '\\u003c')}
        </script>
        <script src="/bundle.js"></script>
      </body>
    </html>
  `);
}

This setup ensures that all asynchronous actions are resolved before the final render, providing a fully populated state for your server-side rendered application.

Conclusion: Harmonizing Your Redux Symphony

Redux Catch Promise offers a powerful way to manage asynchronous actions in your React applications. By extending the capabilities of redux-thunk, it provides a seamless experience for handling complex async flows and implementing server-side rendering.

As you integrate redux-catch-promise into your projects, you’ll find that it harmonizes well with other Redux tools and patterns. For instance, you might explore how it complements libraries like redux-observable for reactive programming or redux-saga for more complex side-effect management.

Remember, while redux-catch-promise is a powerful tool, it’s important to use it judiciously. For simpler applications, the standard redux-thunk might suffice. However, when you need to orchestrate complex asynchronous symphonies or implement server-side rendering with async state, redux-catch-promise shines as a valuable addition to your Redux toolkit.

By mastering redux-catch-promise, you’re adding a versatile instrument to your React development orchestra, enabling you to compose more sophisticated and responsive applications. Happy coding, and may your Redux actions always be in harmony!