refactor(extension): use isFeatureEnabled

[pczeglik-iohk]

Proposed solution

I'm proposing a new (slightly updated) way of using feature flags in the browser extension code base.

Instead of reaching out directly in code to process.env, I've created a helper method isFeatureEnabled which is an abstraction layer on top of process.env. It does the same thing, but in more maintainable way. In the future if we decide to use other solution for feature flags it will be easier to refactor.

Apart of easier usage and better semantic there is one more benefit of this approach. isFeatureEnabled throws Error in case feature flag is not defined in .env.

Ex. Code is using USE_HIDE_MY_BALANCE feature flag, but it is not defined in jest's config file set-env-vars.js

FAIL  src/features/address-book/hooks/__tests__/useGetFilteredAddressBook.test.tsx
  ● Test suite failed to run

    'HIDE_MY_BALANCE' is not set

      29 | export const isFeatureEnabled = (name: FeatureFlag): boolean => {
      30 |   if (!process.env[`USE_${name}`]) {
    > 31 |     throw new Error(`'USE_${name}' is not set`);
         |           ^
      32 |   }
      33 |   return process.env[`USE_${feature}`] === 'true';
      34 | };

Additionally I configured jest to use the same .env file as engineer working with the code. In case there is no .env then .env.defaults will be used.

How to use this helper?

1. Define feature flag in .env.defaults and .env.example (please keep flags sorted) ex. USE_MY_FEATURE=true
2. Extend FeatureFlag type in utils/feature-flags.ts (please keep flags sorted) ex. MY_FEATURE
3. In code instead of using process.env.USE_MY_FEATURE === 'true' use isFeatureEnabled('MY_FEATURE')

[pczeglik-iohk]

This is only sorting. It would be good to have such things sorted so it's easier to manage

[pczeglik-iohk]

If you like this approach, I would like to do similar refactoring to address accessing env vars like getEnvironmentVariable

[pczeglik-iohk]

Use .env file with fallback to .env.defaults instead of manually maintained list of feature flags and env vars

[github-actions]

Allure report

allure-report-publisher generated test report!

smokeTests: ❌ test report for 6957e7dd

	passed	failed	skipped	flaky	total	result
Total	0	31	0	0	31	❌

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

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