write the fibonacci calculator in typescript

I'd be happy to help you with that. Here's a simple implementation of the Fibonacci sequence calculator in TypeScript: ```typescript function fibonacci(n: number): number { if (n <= 1) { return n; } return fibonacci(n - 1) + fibonacci(n - 2); } // Example usage console.log(fibonacci(10)); // Output: 55 ``` This is a basic recursive approach to calculate the Fibonacci sequence. For larger numbers, it's recommended to use an iterative or memoization-based approach to improve performance.