Protected routes in frontend in Supabase - Time & Space Complexity

Time Complexity: Protected routes in frontend

O(n)

Understanding Time Complexity

When using protected routes in a frontend app with Supabase, we want to know how the time to check user access grows as the app handles more pages or users.

We ask: How does the number of checks or API calls change as the app scales?

Scenario Under Consideration

Analyze the time complexity of this simple protected route check.

// Check user session before showing page
const { data: { session } } = await supabase.auth.getSession();
if (!session) {
  redirectToLogin();
} else {
  showProtectedPage();
}

This code checks if a user is logged in before allowing access to a page.

Identify Repeating Operations

Look at what happens repeatedly when users navigate protected pages.

• Primary operation: Calling supabase.auth.getSession() to check user login status.
• How many times: Once per page load or route change that requires protection.

How Execution Grows With Input

As the number of protected pages a user visits grows, the number of session checks grows the same way.

Input Size (n)	Approx. Api Calls/Operations
10 pages visited	10 session checks
100 pages visited	100 session checks
1000 pages visited	1000 session checks

Pattern observation: The number of checks grows directly with the number of protected pages visited.

Final Time Complexity

Time Complexity: O(n)

This means the time spent checking user access grows in a straight line with the number of protected pages visited.

Common Mistake

[X] Wrong: "Checking the user session once means no more checks are needed for other pages."

[OK] Correct: Each protected page load usually triggers a new session check to ensure the user is still logged in and authorized.

Interview Connect

Understanding how protected route checks scale helps you design smooth user experiences and efficient apps. This skill shows you can think about app behavior as it grows.

Self-Check

What if we cached the user session after the first check? How would the time complexity change?