feat: added persisted Switchers for better resource utilization

[petruki]

This pull request introduces several improvements and refactors to the Switcher Client JS SDK, focusing on simplifying the API for checking feature flags, improving switcher instance management, and updating documentation and tests accordingly. The main highlights are the refactoring of the Switcher API to allow calling methods without explicitly passing a feature key each time, the introduction of persisted switcher instances in the Client, and comprehensive updates to documentation and tests to reflect these changes.

API Refactoring and Simplification

• Refactored Switcher methods (isItOn, isItOnBool, isItOnDetail) so that once a switcher is obtained with a key (e.g., Client.getSwitcher('FEATURE01')), subsequent calls to these methods no longer require the key to be passed as an argument. This results in cleaner and less error-prone code.
• Updated all usage examples, tests, and playground scripts to reflect the new API, removing redundant feature key arguments from method calls. [1] [2] [3] [4] [5] [6] [7] [8] [9]

Switcher Instance Management

• Introduced persisted switcher instances in Client.getSwitcher(key). When a switcher is requested with a key, the same instance is returned for subsequent requests with the same key, ensuring consistency and potentially improving performance. [1] [2]
• Added tests to verify that requesting a switcher with the same key returns the same instance, and different keys return different instances.

Documentation and Dependency Updates

• Updated the README.md to clarify the new API usage and terminology, including the distinction between persisted and non-persisted switcher instances. [1] [2] [3]
• Upgraded TypeScript ESLint dependencies in package.json for improved linting support.
• Minor documentation fix in the playground example to reference the correct SDK name.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud