napi_async_init

napi_status napi_async_init(napi_env env,
                            napi_value async_resource,
                            napi_value async_resource_name,
                            napi_async_context* result) 拷贝

• [in] env：调用 API 的环境。

  ¥[in] env: The environment that the API is invoked under.

• [in] async_resource：与异步工作关联的对象，将传递给可能的 async_hooks init 钩子 并可由 async_hooks.executionAsyncResource() 访问。

  ¥[in] async_resource: Object associated with the async work that will be passed to possible async_hooks init hooks and can be accessed by async_hooks.executionAsyncResource().

• [in] async_resource_name：为 async_hooks API 公开的诊断信息提供的资源类型的标识符。

  ¥[in] async_resource_name: Identifier for the kind of resource that is being provided for diagnostic information exposed by the async_hooks API.

• [out] result：初始化的异步上下文。

  ¥[out] result: The initialized async context.

如果 API 成功，则返回 napi_ok。

¥Returns napi_ok if the API succeeded.

async_resource 对象需要保持活动状态直到 napi_async_destroy 才能使 async_hooks 相关 API 正常运行。为了保持与之前版本的 ABI 兼容性，napi_async_context 没有维护对 async_resource 对象的强引用，以避免引入导致内存泄漏。但是，如果 async_resource 在 napi_async_context 被 napi_async_destroy 销毁之前被 JavaScript 引擎垃圾回收，那么在使用 AsyncLocalStorage API 时调用 napi_async_context 相关 API（如 napi_open_callback_scope 和 napi_make_callback）可能会导致异步上下文丢失等问题。

¥The async_resource object needs to be kept alive until napi_async_destroy to keep async_hooks related API acts correctly. In order to retain ABI compatibility with previous versions, napi_async_contexts are not maintaining the strong reference to the async_resource objects to avoid introducing causing memory leaks. However, if the async_resource is garbage collected by JavaScript engine before the napi_async_context was destroyed by napi_async_destroy, calling napi_async_context related APIs like napi_open_callback_scope and napi_make_callback can cause problems like loss of async context when using the AsyncLocalStorage API.

为了保持与以前版本的 ABI 兼容性，为 async_resource 传递 NULL 不会导致错误。但是，不建议这样做，因为这会导致 async_hooks init 钩子 和 async_hooks.executionAsyncResource() 的结果很差，因为底层 async_hooks 实现现在需要资源才能提供异步回调之间的链接。

¥In order to retain ABI compatibility with previous versions, passing NULL for async_resource does not result in an error. However, this is not recommended as this will result poor results with async_hooks init hooks and async_hooks.executionAsyncResource() as the resource is now required by the underlying async_hooks implementation in order to provide the linkage between async callbacks.