Log Javascript Errors On Server

Log Javascript Errors On Server – I used a whole MERN (MySQL, Express, React and Node.js) project that I built from scratch for a handful of blog posts now. As I slowly built it and added more bells and whistles to it, I learned a lot of new things that are worth sharing to help other devs avoid the obstacles I encountered along the way.

Past topics have included using Sequelize as an ORM for a MySQL database, using PassportJS and JWT for authentication and security routing, using Nodemailer to provide email password reset capabilities, etc. Node, plus React, plus basic JavaScript, taught me

Log Javascript Errors On Server

Log Javascript Errors On Server

If you want to see the rest of my posts related to this repo and the code itself, I will link them all at the bottom of this article.

The 10 Most Common Javascript Issues Developers Face

Today I’m talking about how to properly handle errors on both sides of a JavaScript application: from sending errors on the server side in Express, to catching and handling them on the client side with React and Axios.

Log Javascript Errors On Server

Since the server side is where the majority of errors occur, I start with the Node.js / Express server code is also where I start.

I must confess, for some time, while building this app, I received HTTP status code 200 (OK status) back from the Express server even when an error like missing JWT token or user ID was not found the database.

Log Javascript Errors On Server

Best Practices For Node.js Error Handling

I did this because I wanted to send not only an HTTP status code 401 (unauthorized) or 403 (forbidden), but because I also wanted to send a written message about what exactly the error was on the server side, and for time the longest. . , I could not figure out how to do both with Express.

Sends HTTP status 401 or 403 without further information about what went wrong with a

Log Javascript Errors On Server

Then one day, finally, I found the solution I was looking for buried deep in the Express document, which has a lot. And it really wasn’t as difficult as I thought – it was similar to how you send a message along with an HTTP 200 status when something went well, like this:

Fix Javascript Errors That Are Reported In The Console

Can handle objects, strings, or arrays in JavaScript. An example of a success message is in the form of an object with the property of

Log Javascript Errors On Server

While the failure response is just a string because in the case of a successful response things like a message, JSON Web Token or other data can be sent to the client from the server. My errors, however, need nothing more than an HTTP response with an error message as a string. Just to know for the future. 🙂

Below is an example of one of the server side routes in my application that shows the complete application sending either success or failure when a user tries to update their personal information while logged in. a formatted and marked image from VS Code and a code snippet that can be copied).

Log Javascript Errors On Server

Realtime Error Reporting And Logs In Javascript

The first thing that happens when the route is hit is that PassportJS takes over and checks to see if the user’s JSON Web Token exists and is valid, this happens in another file and is covered elsewhere in the -blog so I don’t do that . away in depth about it now.

In the MySQL database, and if found, the user information is updated with a success message with HTTP status 200 and a

Log Javascript Errors On Server

Not found in the database the server logs the error that the user does not exist and sends back an HTTP status 401 with a message that

Logging In Node.js — Trace Your Code

The main piece of code to focus on in terms of error handling is this block here towards the bottom of the file.

Log Javascript Errors On Server

This is about all that has successfully sent both bad status codes and messages from Express to the browser. Now let’s talk about how the browser handles these errors.

For the client side of my full-stack application, I chose to use the very popular Axios promises-based HTTP library instead of the browser’s native lookup API, as I found them easier to work with. This example will show using Axios for all HTTP requests and error handling.

Log Javascript Errors On Server

Flexible Error Handling W/ The Result Class

As I’ve slowly improved my server-side error handling, I’ve also improved my client-side error handling as my application progresses and improves.

Before I got the errors thrown by the right server, this was all I did to interpret the errors.

Log Javascript Errors On Server

I try to catch an error, log its message in the console and then set the state of the React application accordingly. Not terrible for a start, but also not very good for a final solution – the second I try to throw something from HTTP status 200 with a message, the client would just explode in there.

Rethinking Frontend Error Reporting

And just like the server side, I finally got tired of handling this half-baked error I made and found some better Axios documentation on how the library wants you to handle errors, which I ignored earlier.

Log Javascript Errors On Server

With that one revelation, suddenly catching the error on the client’s side suddenly became easier and descriptive.

The way Axios interprets success responses from the server is almost exactly the same as it interprets error codes.

Log Javascript Errors On Server

Logging Script Errors In Javascript

Again, here is a great snippet of the file where a user updates the data on the client side and sends it to be saved in the database.

UpdateProfile.js shows the client-side update requests sent to the server, whether it works or not.

Log Javascript Errors On Server

Is logged in the console to help the developer understand what went wrong and the state of the application

Logging Server · Github Topics · Github

This is what a user would see if the dev tools console was open when the request failed.

Log Javascript Errors On Server

The client sees the 401 status code the user sends back along with the message from the server saying that no user was found in the database with a matching username.

This concludes my explanation of how the client can handle and display the errors thrown by the server. Again, it’s not too hard to figure out, but putting it all together can sometimes prove to be the hardest part of all.

Log Javascript Errors On Server

Log Messages In The Console

Errors in the codes such as death and taxes, are bound to happen. Our job as developers is to make sure we know when they arrive and handle them gracefully so the user can have a good experience with our apps.

Although this kind of thing is commonplace and important, sometimes the documentation on error handling like this is buried deep or somewhat cryptic with the bare-bones pieces of code provided. That’s why I wanted to write today detailing exactly how to pass error codes and messages from Express all the way to the Axios library used on the React front end.

Log Javascript Errors On Server

Check back in a few weeks, I’ll write more about JavaScript, React, ES6 or anything else related to web development. Follow me so you don’t miss out!

Node Error Logging

Thanks for reading, I hope I have given you some good solutions on how to handle errors in your full stack JavaScript applications in the future. Mistakes will happen – let’s handle them well.

Log Javascript Errors On Server

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Staff Software Engineer, formerly a digital marketer. Frontend dev is my focus, but I’m always ready to learn new things. Say hello: www.paigeniedringhaus.com It is not enough to have a central log and error logging system: good logs are characterized by immediate updates in real time. There is a good reason for this, but yes, as you never know what your customers are going through when using your product because you are not standing behind them and guiding them. Therefore, we need a way to notify them when they encounter unexpected behavior.

Log Javascript Errors On Server

A Definitive Guide To Handling Errors In Javascript

The most common way to achieve real-time error reporting is monitoring and notification. Both approaches are good as long as they are used in the right situations. What is interesting about these approaches is that they share a common feature, which is to provide log information immediately generated by all connected clients.

This article explains a practical approach using Pusher, a real-time Pub/Sub service, to monitor errors (especially non-catchable ones) when they are thrown.

Log Javascript Errors On Server

We will create a basic browser application that simulates a real-life application that throws an error. We will throw errors intentionally by clicking a button or two. The plan is, when this error is thrown, a global error event handler is set up whose handler is sent as a request to a server via XHR.

A Javascript Error Occurred In The Main Process [discord]

The server will then use the Pusher trigger to issue the event that an error has occurred so that all connected clients can subscribe to the event. In our case, we have only one client connected which shows error as real time map.

Log Javascript Errors On Server

The first thing we need to work on is the client that has the button that sends the errors. In principle,

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