Type (function signature) is not assignable to type ‘never’ when exporting

Type (function signature) is not assignable to type ‘never’ when exporting

If you’re working with TypeScript and have encountered the error message “Type (function signature) is not assignable to type ‘never’ when exporting,” you’re not alone. This error can be quite confusing, but fear not, as we’ll explore the possible solutions to resolve this issue.

Solution 1: Check the exported function signature

One possible reason for this error is an incorrect function signature in the exported function. Make sure that the function signature matches the expected type. Here’s an example:

    
      export function myFunction(param: string): void {
        // Function implementation goes here
      }
    
  

In the above code snippet, we’re exporting a function called myFunction that takes a parameter of type string and returns void. Ensure that your function signature aligns with the expected type.

Solution 2: Check the import statement

Another possible reason for this error is an issue with the import statement. Verify that you’re importing the function correctly and using the correct syntax. Here’s an example:

    
      import { myFunction } from './myModule';
      
      // Use the imported function
      myFunction('Hello, TypeScript!');
    
  

In the above code snippet, we’re importing the myFunction from a module called myModule. Ensure that your import statement is correct and matches the module and function names.

Solution 3: Check for circular dependencies

Circular dependencies can also cause the “Type (function signature) is not assignable to type ‘never’” error. Make sure that you don’t have any circular dependencies in your codebase. Circular dependencies occur when two or more modules depend on each other.

To resolve circular dependencies, you can refactor your code to remove the dependency or use techniques like lazy loading or dependency injection. Analyze your codebase and identify any circular dependencies to resolve this issue.

Conclusion

Encountering the “Type (function signature) is not assignable to type ‘never’” error in TypeScript can be frustrating, but with the solutions mentioned above, you should be able to resolve the issue. Remember to check the function signature, import statement, and for any circular dependencies. By following these steps, you’ll be on your way to successfully exporting your functions without any errors.