How to fix Namespace 'X' already has a declaration with different structure in TypeScript

# Search for namespace declarations
grep -r "namespace\s*NamespaceName" src/
grep -r "declare\s*namespace\s*NamespaceName" ./

// File 1
namespace MyNamespace {
  export const value: string;
}

// File 2 - ERROR: Different type
namespace MyNamespace {
  export const value: number; // Conflict!
}

// File 1
namespace MyNamespace {
  export function doSomething(): void;
}

// File 2
namespace MyNamespace {
  // Missing doSomething() - OK for merging
  export function doAnotherThing(): void;
}

// File 1
namespace MyNamespace {
  export const config: Config; // Variable
}

// File 2 - ERROR: Different kind
namespace MyNamespace {
  export function config(): Config; // Function - Conflict!
}

// Instead of conflicting specific types:
namespace MyNamespace {
  export const value: string; // File 1
  export const value: number; // File 2 - ERROR!
}

// Use a union type in a single declaration:
namespace MyNamespace {
  export const value: string | number;
}

// Or use conditional exports based on environment:
namespace MyNamespace {
  export const value: string;
}

// In another file for specific environment:
declare module './my-namespace' {
  namespace MyNamespace {
    // Only augment if not already defined
    export const value?: number;
  }
}

// Base declaration
declare namespace MyLib {
  interface Config {
    timeout: number;
  }
}

// Correct augmentation
declare namespace MyLib {
  interface Config {
    retries?: number; // Adding optional property - OK
  }
}

namespace MyNamespaceV1 { /* ... */ }
namespace MyNamespaceV2 { /* ... */ }

npm list @types/package-name
# Or for yarn:
yarn why @types/package-name

npm uninstall @types/conflicting-package
# Or specify exact version:
npm install @types/[email protected]

{
  "typesVersions": {
    ">=4.0": { "*": ["ts4.0/*"] }
  }
}

{
  "compilerOptions": {
    "skipLibCheck": true
  }
}

# Delete output directories
rm -rf dist/ build/ node_modules/.cache/

# Or use TypeScript's --clean flag
npx tsc --clean

npx tsc --noEmit

npm run build
# or
yarn build