Can you explain the purpose and use of the typedef keyword in Dart?

In Dart language, the keyword typedef is used to declare type aliases, most often for defining new names for function types. This helps make the code more readable and maintainable, especially when functions have complex signatures.

For example, if you have a function that takes another function with a specific signature, you can define a typedef for that signature:

typedef IntOperation = int Function(int a, int b);

int add(int a, int b) => a + b;

void performOperation(IntOperation operation) {
  print(operation(2, 3));
}

void main() {
  performOperation(add); // Outputs 5
}

Thus, typedef simplifies working with function types and improves code readability.