You can specify types for a function's parameters and return value. This ensures the function is used correctly.
typescript
// This function takes two numbers and returns a number
function add(a: number, b: number): number {
return a + b;
}
// This function doesn't return anything (void)
function logMessage(message: string): void {
console.log(message);
}
let sum: number = add(5, 10);
logMessage("The sum is " + sum);You should see
The sum is 15