fix: Throw ConfigurationError when invalid Auth0Client configuration

[tusharpandey13]

This PR enhances the configuration validation in the Auth0Client class by adding a dedicated error class for configuration errors and improving error reporting.

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

📋 Changes

1. Added a new ConfigurationError class
2. Added validation for required options for Auth0Client
3. Added tests for the same
4. Updated documentation

📎 References

🎯 Testing

PASSING

 Test Files  11 passed (11)
      Tests  174 passed (174)
   Start at  12:31:14
   Duration  803ms (transform 410ms, setup 0ms, collect 1.37s, tests 205ms, environment 1ms, prepare 509ms)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 79.65%. Comparing base (51deff0) to head (0f57478).

Files with missing lines	Patch %	Lines
src/errors/index.ts	92.00%	2 Missing ⚠️
src/server/client.ts	98.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2026      +/-   ##
==========================================
+ Coverage   74.82%   79.65%   +4.83%     
==========================================
  Files          21       21              
  Lines        1863     1922      +59     
  Branches      289      314      +25     
==========================================
+ Hits         1394     1531     +137     
+ Misses        462      385      -77     
+ Partials        7        6       -1     

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these review comments have been resolved

[ik-southpole]

Again breaking change... below was used to be a valid setup. We could run build and provide those envs in runtime. Now, build fails with the error.

import { Auth0Client } from "@auth0/nextjs-auth0/server";

const auth0 = new Auth0Client({
  domain: process.env.AUTH0_DOMAIN,
  secret: process.env.AUTH0_SECRET,
  appBaseUrl: process.env.APP_BASE_URL,
  clientId: process.env.AUTH0_CLIENT_ID,
  clientSecret: process.env.AUTH0_CLIENT_SECRET,
  authorizationParameters: { scope: "openid profile email offline_access" },
});

export default auth0;

[ik-southpole]

How to initialise Auth0Client with params provided in runtime (affected after updating from v4.4.0 to v4.4.1)?

[jgeurts]

Like @ik-southpole mentioned, this caused a breaking change to us as well. Please use the proper semantic title for breaking changes.

[mdedys]

Again breaking change... below was used to be a valid setup. We could run build and provide those envs in runtime. Now, build fails with the error.

import { Auth0Client } from "@auth0/nextjs-auth0/server";

const auth0 = new Auth0Client({
  domain: process.env.AUTH0_DOMAIN,
  secret: process.env.AUTH0_SECRET,
  appBaseUrl: process.env.APP_BASE_URL,
  clientId: process.env.AUTH0_CLIENT_ID,
  clientSecret: process.env.AUTH0_CLIENT_SECRET,
  authorizationParameters: { scope: "openid profile email offline_access" },
});

export default auth0;

This is a breaking change for us as well