Maximizing Debuggability with Redux – LogRocket

Maximizing Debuggability with Redux  #javascript #react #logging #debugging #redux #reactjs

  • By using front end logging tools like LogRocket, developers can easily understand and fix tricky bugs in production by reviewing the actions and state changes leading up to a bug.While this information is immediately useful in any Redux app, there is a lot more we can achieve by architecting an app with logging in mind.
  • When debugging issues, we can dig into this state object to see information on in-flight requests, queryCount (if we’re polling on a query), and timings.Storing this information in Redux is critical, since it puts full context on all network activity in the Redux logs.Rolling your own data fetching “framework”If you’d prefer a simpler approach, you can roll your own data fetching “framework” by simply dispatching explicit actions when querying and receiving data from the network.For example, lets say we’re building a blogging app.
  • This would then update state appropriately to:postsQuery: { url: ‘’, isPending: true, data: […],}This example is far from thorough, but the idea is that by being explicit with Redux actions for each part of the request lifecycle, it becomes easy to debug any potential race condition or network error.Handling other sources of non-determinismIn addition to network fetching, there are lots of other sources of non-determinism that can cause bugs.
  • For example:myWebSocket.onmessage = function (event) { store.dispatch({ type: ‘BLOG_POST_UPDATE_RECEIVED’, payload: event, } store.dispatch({ type: ‘BLOG_POST_UPDATE_RECEIVED’, payload: event, }That way, when looking at the Redux logs for an error or user-reported issue, we can see all the data that was received over the websocket and, crucially, relate it in time to other redux actions and network requests.Local StorageOften, an app needs to read from local storage when it first starts up.
  • Once you get the library set up, you’ll see a new key in your Redux store called routing with information on the current router state.In addition, react-router-redux dispatches actions like @@router/LOCATION_CHANGE when its state changes.Also of note is that using react-router-redux lets you rewind router state when time-traveling in redux-devtools, since its state its state is derived from the state in Redux.A note about local vs Redux stateI don’t want to get into the debate on local vs Redux state here, but production Redux logging does change the calculus of this decision in some cases.

In my last blog post, Redux Logging in Production, I discussed one of the most important benefits of using Redux — debuggability. By using front end logging tools like LogRocket, developers can…
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