Alerty Blog

Understanding NextJS Error Handling Techniques And Best Practices

Written by Jack Dwyer | Jul 9, 2024 10:22:57 AM

While navigating vercel logging, have you ever encountered confusing Next.js errors that blocked your progress? NextJS error handling is a key skill for any developer. 

But what if I told you there is an even more efficient way to handle NextJS errors than traditional logging? Alerty's solution, NextJS logging, provides valuable insights to help you understand error handling in Next.js and React.

Table of Contents

Why Is Error Handling Important?

When developing a web application, errors are inevitable. Whether it’s due to faulty code, server connectivity issues, or user error, a bug-free application is merely a utopian concept. How your application responds to these errors determines your software's overall health and, ultimately users' satisfaction. That's why having well-defined and organized error-handling techniques is a must.

Various errors may occur in a React application developed with the NextJS framework. These can largely be classified into:

1. Syntax Errors

These are errors caused by incorrect syntax or coding logic in the application, which can cause it to crash.

2. Runtime Errors

These are unexpected situations that arise while the application runs.

3. Logical Errors

These errors may not necessarily result in a crash but produce incorrect results or perform unintended actions.

Aiming for perfection in code is great, but make sure your aim for perfection also extends to your error management!

What Is Error.js And How Does It Work In NextJS?

Error.js in NextJS

The error.js file convention in NextJS gracefully handles unexpected runtime errors in nested routes. It automatically wraps a route segment and its nested children in a React error boundary. It creates an error UI tailored to specific segments using the file-system hierarchy to adjust granularity. This mechanism helps isolate errors to affected segments while keeping the rest of the application functional. It allows adding functionality to recover from an error without a full page reload.

The React component exported from the error.js file serves as a fallback component when an error is thrown within the error boundary. This feature helps contain errors and render the fallback component when needed. The fallback error component allows layouts above the error boundary to maintain their state and remain interactive, while the error component can display functionality to recover from the error.

NextJS logging

Alerty offers a cloud monitoring service for developers and early-stage startups, providing:

  • Application performance monitoring
  • Database monitoring
  • Incident management

Broad Technology Support

Supporting technologies like NextJS, React, Vue, and Node.js, Alerty helps developers identify and fix issues efficiently. It monitors databases such as Supabase, PostgreSQL, and RDS, tracking essential metrics such as CPU usage and memory consumption. With quick incident management and Real User Monitoring (RUM) capabilities, Alerty optimizes user experience, covering dependencies like Stripe API, OpenAI, and Vercel with its universal service monitoring feature. 

AI-Powered Efficiency

Using AI for simplified setup, Alerty offers a cost-effective solution compared to competitors, designed for ease of use and rapid integration with tools like Sentry, making it ideal for developers and small teams in need of efficient and affordable monitoring. Enhance your application's performance and catch issues before they affect users with Alerty's NextJS logging tool today!

Related Reading

NextJS Error Handling: How To Handle Errors In NextJS

Recovering From Errors

If an error is temporary, retrying might fix it. Using the reset() function in an error component prompts users to try again. When reset() the Error Boundary attempts to re-render its contents. If successful, the fallback error component is replaced with the new result.

'use client'

 

export default function Error({

  error,

  reset,

}: {

  error: Error & { digest?: string }

  reset: () => void

}) {

  return (

    <div>

      <h2>Something went wrong!</h2>

      <button onClick={() => reset()}>Try again</button>

    </div>

  )

}

Nested Routes

Nested Routes in React involve rendering components in a structured hierarchy. For instance, consider a scenario where two nested segments each contain layout.js and error.js files. This creates a hierarchy like this:

Nested Error Component Hierarchy

Errors propagate upwards to the nearest parent error boundary. An error.js file will manage errors for all its nested child segments. Positioning error.js files at various levels within the nested route folders allows for adjustments to the granularity of the error UI.

An error boundary defined in an error.js file won't handle errors from a layout.js component in the same segment, as the error boundary is nested within that layout's component.

Handling Errors in Layouts

error.js boundaries do not catch errors thrown in layout.js or template.js components of the same segment. This intentional hierarchy keeps important UI shared between sibling routes (such as navigation) visible and functional when an error occurs.

  • Place an error.js file in the layout's parent segment to handle errors within a specific layout or template.
  • To handle errors within the root layout or template, use a variation of error.js called global-error.js.

Handling Errors in Root Layouts

The root app/error.js boundary does not catch errors thrown in the root app/layout.js or app/template.js components. To handle errors specifically in these root components, use a variation of error.js called app/global-error.js located in the root app directory. Unlike the root error.js, the global-error.js error boundary wraps the entire application, and its fallback component replaces the root layout when active. Because of this, it is important to note that global-error.js must define its own <html> and <body> tags.

global-error.js is the least granular error UI and can be considered "catch-all" error handling for the whole application. It is unlikely to be triggered often as root components are typically less dynamic, and other error.js boundaries will catch most errors. Even if a global-error.js is defined, it is still recommended to define a root error.js whose fallback component will be rendered within the root layout, which includes globally shared UI and branding.

'use client'

 

export default function GlobalError({

  error,

  reset,

}: {

  error: Error & { digest?: string }

  reset: () => void

}) {

  return (

    <html>

      <body>

        <h2>Something went wrong!</h2>

        <button onClick={() => reset()}>Try again</button>

      </body>

    </html>

  )

Handling Server Errors

If an error is thrown inside a Server Component, Next.js will forward an Error object (stripped of sensitive error information in production) to the nearest error.js file as the error prop.

Securing Sensitive Error Information

The Error object forwarded to the client only includes a generic message and digest property during production. This is a security precaution to avoid leaking potentially sensitive details included in the error to the client.

The message property contains a generic message about the error. The digest property contains an automatically generated hash of the error that can be used to match the corresponding error in server-side logs. During development, the Error object forwarded to the client will be serialized and include the message of the original error for easier debugging.

6 Best Practices For NextJS Error Handling

1. Use NextJS Error Boundaries

Error boundaries are React components that catch Javascript errors in their child component tree. You can elegantly handle these errors by putting a catch-all error boundary at the root level of your application.

2. Integration with Troubleshooting Online Tools

Incorporating third-party tools like Alerty can capture exceptions, provide stack traces, and insights into how, when, and why the error occurred, simplifying the debugging process.

3. Custom 404 and 500 Pages

Create custom 404 and 500 pages to handle failed HTTP queries and server errors, providing a seamless and user-friendly experience despite errors.

4. API Error Handling

When data fetch fails, provide users with informative error messages using the catch method combined with async/await to encapsulate the failure scenario neatly.

5. Provide Meaningful Error Messages

Avoid generic error messages like "An error occurred" and provide users with specific information about the issue, enhancing the user experience.

6. Centralize Error Handling

Enhance maintainability and consistency by developing a centralized error-handling module containing the following:

  • Custom error classes
  • Utility functions
  • Consistent error response format

Related Reading

Catch Issues Before They Affect Your Users with Alerty's NextJS Logging Tool

Alerty is a vital cloud monitoring service designed explicitly for developers and early-stage startups. This powerful tool offers various services, including:

  • Application performance monitoring
  • Database monitoring
  • Incident management

If you're using technologies like NextJS, React, Vue, or Node.js, Alerty is the solution you've been looking for. It supports databases such as Supabase, PostgreSQL, and RDS and monitors key metrics like CPU usage and memory consumption. 

Incident Management with Alerty

Incident management is crucial when it comes to monitoring. Alerty excels in offering quick incident management capabilities, ensuring you catch issues before they affect your users. Using Real User Monitoring (RUM), Alerty helps you optimize the user experience. This feature allows you to identify problems before they spiral out of control.

Universal Service Monitoring with Alerty

Alerty goes a step further by providing Universal Service Monitoring. This feature covers your dependencies, whether using:

  • Stripe API
  • OpenAI
  • Vercel

With Alerty, you can rest easy knowing that all your dependencies are under surveillance, ensuring smooth functionality and flawless user experiences.

AI-Powered Simplicity with Alerty

Alerty leverages the power of AI to simplify setup processes. It is an excellent choice for developers and small teams because it provides a cost-effective solution compared to competitors. Its ease of use and quick setup make it a go-to tool for those who need efficient, affordable monitoring. Alerty seamlessly integrates with tools like Sentry, offering a comprehensive solution for your monitoring needs.

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