chore: add TypeScript `Strict Mode` Support for the packages

Start with the package-level tsconfig.json for @asgardeo/javascript, then follow the listed package order and inspect the affected *.ts and *.tsx files. Enable strict mode, resolve the resulting type issues, update CI and contributing documentation, and verify that all packages pass strict checking.

Current Limitation

Currently, TypeScript strict mode is not consistently enabled across all packages in the monorepo. This leads to:

• Potential runtime errors that could be caught at compile time
• Implicit any types that reduce type safety
• Missing null/undefined checks that could cause runtime issues
• Inconsistent type checking standards across different packages
• Reduced developer experience due to less precise type inference

Without strict mode enabled, the codebase may contain:

• Functions with implicit return type any
• Variables that could be null or undefined without proper checks
• Less strict function parameter checking
• Weaker type checking for object property access

Suggested Improvement

Enable TypeScript strict mode across all packages and fix related type issues:

Implementation Plan

[!NOTE]
Start with the following order:

1. @asgardeo/javascript
2. @asgardeo/browser
3. @asgardeo/react
4. @asgardeo/node
5. @asgardeo/nextjs

1. Enable strict mode in tsconfig.json files

   • Add "strict": true to all package-level tsconfig.json files
   • Ensure consistent strict mode configuration across the monorepo

2. Fix type errors systematically

   • Address implicit any types by adding proper type annotations
   • Add null/undefined checks where needed using optional chaining and nullish coalescing
   • Fix function return type annotations
   • Resolve strict property initialization issues

3. Update build process

   • Ensure CI/CD pipeline fails on strict mode violations
   • Update lint rules to complement strict mode checks

4. Documentation updates

   • Update contributing guidelines to mention strict mode requirements
   • Add examples of proper typing patterns

Files to be updated

• packages/*/tsconfig.json - Enable strict mode
• Various *.ts and *.tsx files - Fix type issues
• CI configuration - Ensure strict checking in build pipeline]

Please select the package issue is related to

@asgardeo/express, @asgardeo/browser, @asgardeo/javascript, @asgardeo/nextjs, @asgardeo/node, @asgardeo/nuxt, @asgardeo/react, @asgardeo/react-router, @asgardeo/vue

Version

current

Reporter Checklist

• I have searched the existing issues and this is not a duplicate.
• I have provided all the necessary information.
• I have verified the improvement is not available in the latest version of the package.