src: factor out Node.js-agnostic N-APIs

Split the Node.js ECMAScript API (N-EAPI?) into its own header and
implementation files. The motivation is that the ECMAScript API stand
on its own so it might be embedded separately, implementation and all.

Portions of the implementation used by both files are stored in
`node_api_impl.h`.

The checked boxes below indicate that the given API remains in
`node_api.h`, whereas the lack of a checkbox indicates that the API was
moved to `node_ecma_api.h`.

* [x] NAPI_MODULE
* [x] NAPI_MODULE_INIT
* [x] napi_acquire_threadsafe_function
* [x] napi_add_env_cleanup_hook
* [x] napi_async_destroy
* [x] napi_async_init
* [x] napi_call_threadsafe_function
* [x] napi_cancel_async_work
* [x] napi_close_callback_scope
* [x] napi_create_async_work
* [x] napi_create_buffer
* [x] napi_create_buffer_copy
* [x] napi_create_external_buffer
* [x] napi_create_threadsafe_function
* [x] napi_delete_async_work
* [x] napi_fatal_error
* [x] napi_fatal_exception
* [x] napi_get_buffer_info
* [x] napi_get_node_version
* [x] napi_get_threadsafe_function_context
* [x] napi_get_uv_event_loop
* [x] napi_is_buffer
* [x] napi_make_callback
* [x] napi_module_register
* [x] napi_open_callback_scope
* [x] napi_queue_async_work
* [x] napi_ref_threadsafe_function
* [x] napi_release_threadsafe_function
* [x] napi_remove_env_cleanup_hook
* [x] napi_unref_threadsafe_function
* [ ] napi_add_finalizer
* [ ] napi_adjust_external_memory
* [ ] napi_call_function
* [ ] napi_close_escapable_handle_scope
* [ ] napi_close_handle_scope
* [ ] napi_coerce_to_bool
* [ ] napi_coerce_to_number
* [ ] napi_coerce_to_object
* [ ] napi_coerce_to_string
* [ ] napi_create_array
* [ ] napi_create_arraybuffer
* [ ] napi_create_array_with_length
* [ ] napi_create_bigint_int64
* [ ] napi_create_bigint_uint64
* [ ] napi_create_bigint_words
* [ ] napi_create_dataview
* [ ] napi_create_double
* [ ] napi_create_error
* [ ] napi_create_external
* [ ] napi_create_external_arraybuffer
* [ ] napi_create_function
* [ ] napi_create_int32
* [ ] napi_create_int64
* [ ] napi_create_object
* [ ] napi_create_promise
* [ ] napi_create_range_error
* [ ] napi_create_reference
* [ ] napi_create_string_latin1
* [ ] napi_create_string_utf16
* [ ] napi_create_string_utf8
* [ ] napi_create_symbol
* [ ] napi_create_typedarray
* [ ] napi_create_type_error
* [ ] napi_create_uint32
* [ ] napi_define_class
* [ ] napi_define_properties
* [ ] napi_delete_element
* [ ] napi_delete_property
* [ ] napi_delete_reference
* [ ] napi_escape_handle
* [ ] napi_get_and_clear_last_exception
* [ ] napi_get_arraybuffer_info
* [ ] napi_get_array_length
* [ ] napi_get_boolean
* [ ] napi_get_cb_info
* [ ] napi_get_dataview_info
* [ ] napi_get_element
* [ ] napi_get_global
* [ ] napi_get_last_error_info
* [ ] napi_get_named_property
* [ ] napi_get_new_target
* [ ] napi_get_null
* [ ] napi_get_property
* [ ] napi_get_property_names
* [ ] napi_get_prototype
* [ ] napi_get_reference_value
* [ ] napi_get_typedarray_info
* [ ] napi_get_undefined
* [ ] napi_get_value_bigint_int64
* [ ] napi_get_value_bigint_uint64
* [ ] napi_get_value_bigint_words
* [ ] napi_get_value_bool
* [ ] napi_get_value_double
* [ ] napi_get_value_external
* [ ] napi_get_value_int32
* [ ] napi_get_value_int64
* [ ] napi_get_value_string_latin1
* [ ] napi_get_value_string_utf16
* [ ] napi_get_value_string_utf8
* [ ] napi_get_value_uint32
* [ ] napi_get_version
* [ ] napi_has_element
* [ ] napi_has_named_property
* [ ] napi_has_own_property
* [ ] napi_has_property
* [ ] napi_instanceof
* [ ] napi_is_array
* [ ] napi_is_arraybuffer
* [ ] napi_is_dataview
* [ ] napi_is_error
* [ ] napi_is_exception_pending
* [ ] napi_is_promise
* [ ] napi_is_typedarray
* [ ] napi_new_instance
* [ ] napi_open_escapable_handle_scope
* [ ] napi_open_handle_scope
* [ ] napi_reference_ref
* [ ] napi_reference_unref
* [ ] napi_reject_deferred
* [ ] napi_remove_wrap
* [ ] napi_resolve_deferred
* [ ] napi_run_script
* [ ] napi_set_element
* [ ] napi_set_named_property
* [ ] napi_set_property
* [ ] napi_strict_equals
* [ ] napi_throw
* [ ] napi_throw_error
* [ ] napi_throw_range_error
* [ ] napi_throw_type_error
* [ ] napi_typeof
* [ ] napi_unwrap
* [ ] napi_wrap

PR-URL: https://github.com/nodejs/node/pull/23786
Reviewed-By: Yazhong Liu <yorkiefixer@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/doc/api/n-api.md b/doc/api/n-api.md
index 27ebefb4b5..33d9f561be 100644
--- a/doc/api/n-api.md
+++ b/doc/api/n-api.md
@@ -155,6 +155,65 @@ available to the module code.
 
 \* Indicates that the N-API version was released as experimental
 
+The N-APIs associated strictly with accessing ECMAScript features from native
+code can be found separately in `js_native_api.h` and `js_native_api_types.h`.
+The APIs defined in these headers are included in `node_api.h` and
+`node_api_types.h`. The headers are structured in this way in order to allow
+implementations of N-API outside of Node.js. For those implementations the
+Node.js specific APIs may not be applicable.
+
+The Node.js-specific parts of an addon can be separated from the code that
+exposes the actual functionality to the JavaScript environment so that the
+latter may be used with multiple implementations of N-API. In the example below,
+`addon.c` and `addon.h` refer only to `js_native_api.h`. This ensures that
+`addon.c` can be reused to compile against either the Node.js implementation of
+N-API or any implementation of N-API outside of Node.js.
+
+`addon_node.c` is a separate file that contains the Node.js specific entry point
+to the addon and which instantiates the addon by calling into `addon.c` when the
+addon is loaded into a Node.js environment.
+
+```C
+// addon.h
+#ifndef _ADDON_H_
+#define _ADDON_H_
+#include <js_native_api.h>
+napi_value create_addon(napi_env env);
+#endif  // _ADDON_H_
+```
+
+```C
+// addon.c
+#include "addon.h"
+napi_value create_addon(napi_env env) {
+  napi_value result;
+  assert(napi_create_object(env, &result) == napi_ok);
+  napi_value exported_function;
+  assert(napi_create_function(env,
+                              "doSomethingUseful",
+                              NAPI_AUTO_LENGTH,
+                              DoSomethingUseful,
+                              NULL,
+                              &exported_function) == napi_ok);
+  assert(napi_set_named_property(env,
+                                 result,
+                                 "doSomethingUseful",
+                                 exported_function) == napi_ok);
+  return result;
+}
+```
+
+```C
+// addon_node.c
+#include <node_api.h>
+
+static napi_value Init(napi_env env, napi_value exports) {
+  return create_addon(env);
+}
+
+NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)
+```
+
 ## Basic N-API Data Types
 
 N-API exposes the following fundamental datatypes as abstractions that are