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In our previous article Blazor WASM Exception Handling and Error Boundary, we learnt how global exception works and how to handle exceptions using built in ErrorBoundary component. In this article, let's learn about Error Logging in Blazor WASM.

Logging is needed in all applications. This will help to find root cause or track user activity in any environment. This can be done easily in server side applications with logging frameworks but for SPA like Blazor WASM running in browser sandbox, we will not be having direct access to file system or database and logging cannot be done like how we do in server side applications. We can use browser console to log Information, Warning or Error. But this will not help much in production. We can still make logging happen in production by processing Exception and posting the error details to backend API. Let's look on how to achieve this in Blazor WASM.

Let's start with simple Subscription component. This will throw error on Subscribe Now button click.

To process the error, let's create an Error component. This component takes Child Content RenderFragment as input. This component also has ProcessError method to process the exception and log it to browser console or backend API. For simplicity I'm logging into browser console.

Now lets wrap our Subscription component with Error component.

That's it. Now if any exception occurs, Sunscription component will make use of CascadingParameter Error component and process the exception which then can be used to log to browser console or posted to backend API.