Overcoming Geo-Blocked Features in TypeScript: A Senior Architect’s Approach

Source: Dev.to

Understanding the Challenge

Geo-blocking typically relies on detecting the user’s IP location and restricting or altering feature accessibility. Since many legacy systems or poorly documented codebases lack explicit markers or configurations for geolocation, a senior architect must approach this problem systematically. The key is to simulate different geographies during testing to verify feature accessibility — all within a TypeScript environment.

Strategy Outline

We will focus on three core steps:

• Mock environment variables or APIs to simulate different user locations.
• Create test wrappers or utilities to streamline location‑based testing.
• Implement comprehensive tests that verify feature accessibility across geographies.

Step 1: Mocking Geolocation in TypeScript

Since we often lack direct documentation, it’s crucial to identify how the system detects location. Commonly, IP‑based geolocation is called via an external API or embedded service. Here’s how to mock it:

// geoLocationService.ts
export interface Location {
  countryCode: string;
  city?: string;
}

export function fetchUserLocation(): Promise {
  // In production, this would call an external API
  return fetch('/api/location')
    .then(res => res.json());
}

// Mock this during tests
export function mockLocation(location: Location) {
  (fetchUserLocation as any) = () => Promise.resolve(location);
}

In your tests, you can override fetchUserLocation to simulate different locations.

Step 2: Building Location‑Aware Test Utilities

Creating a utility function that wraps feature checks based on location helps automate testing:

export async function testFeatureAccess(
  feature: string,
  allowedCountries: string[]
): Promise {
  const location = await fetchUserLocation();
  if (allowedCountries.includes(location.countryCode)) {
    console.log(`Feature ${feature} should be accessible in ${location.countryCode}`);
    return true;
  } else {
    console.log(`Feature ${feature} is restricted in ${location.countryCode}`);
    return false;
  }
}

This abstraction allows you to specify which countries should have access, then verify programmatically.

Step 3: Implementing Robust Tests

Automate testing across multiple geographies with synthetic data:

import { mockLocation, testFeatureAccess } from './geoUtils';

describe('Geo-blocked features test', () => {
  const featureName = 'PremiumContent';
  const allowedCountries = ['US', 'GB', 'CA'];

  const testLocations = [
    { countryCode: 'US' },
    { countryCode: 'FR' },
    { countryCode: 'CA' },
    { countryCode: 'JP' }
  ];

  testLocations.forEach(location => {
    it(`should verify access in ${location.countryCode}`, async () => {
      mockLocation(location);
      const hasAccess = await testFeatureAccess(featureName, allowedCountries);
      if (allowedCountries.includes(location.countryCode)) {
        expect(hasAccess).toBe(true);
      } else {
        expect(hasAccess).toBe(false);
      }
    });
  });
});

Final Thoughts

Dealing with geo‑restrictions without explicit documentation requires a flexible, test‑driven approach. By simulating geolocation data and automating tests, senior architects can ensure feature accessibility aligns with business and legal requirements. Keep your environment modular, and always document the geolocation flow as soon as possible to streamline future development efforts.

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