Fluent-State lacks a way to intercept and modify state transitions before they occur. Adding fluentState.use((prev, next, transition) => {...}) allows developers to implement logging, security checks, or validation before proceeding.

Example Usage:

fluentState.use((prev, next, transition) => {
  console.log(`Checking transition: ${prev} → ${next}`);

  if (next === 'mainApp' && !userHasAccess()) {
    console.log("Access Denied!");
    return; // Prevents transition
  }

  transition(); // Proceed to next state
});

Acceptance Criteria (AC):

• Middleware should run before transitioning to the next state.
• If transition() is not called, the transition should be blocked.
• Multiple middleware functions should execute in order.
• Existing unit tests pass.
• Add new unit tests for all AC.
• Test cases should include middleware execution and blocking transitions.