napi_env indicates the running status and context information of an application. The value of napi_env may change in different call contexts, execution environments, during Node-API module initialization or destruction, and in multi-threaded environments. napi_env should be safely accessed and manipulated through the APIs provided by Node-API.
The reasons for prohibiting caching of napi_env are as follows:
- Maintain context consistency: If napi_env is cached, the cached data may become inconsistent with that in the latest environment. For example, if certain variables in the environment are modified during an API call but the cached data is not updated, unexpected result may be returned, leading to logical errors or exceptions in the application.
- Avoid cross-thread use: napi_env cannot be shared or passed between different threads. If it is cached and used in different threads, thread safety issues may occur. However, napi_env can be cached if it is used only in the main thread.
- Improve application reliability and stability: Prohibiting the caching of napi_env ensures that the latest and valid context environment is used each time a Node-API function is called, avoiding potential errors and exceptions.