n-api: implement promise

Promise is implemented as a pair of objects. `napi_create_promise()`
returns both a JavaScript promise and a newly allocated "deferred" in
its out-params. The deferred is linked to the promise such that the
deferred can be passed to `napi_resolve_deferred()` or
`napi_reject_deferred()` to reject/resolve the promise.

`napi_is_promise()` can be used to check if a `napi_value` is a native
promise - that is, a promise created by the underlying engine, rather
than a pure JS implementation of a promise.

PR-URL: https://github.com/nodejs/node/pull/14365
Fixes: https://github.com/nodejs/abi-stable-node/issues/242
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/node_api.h b/src/node_api.h
index e52e2016d7..6a4b294187 100644
--- a/src/node_api.h
+++ b/src/node_api.h
@@ -543,6 +543,20 @@ NAPI_EXTERN
 napi_status napi_get_node_version(napi_env env,
                                   const napi_node_version** version);
 
+// Promises
+NAPI_EXTERN napi_status napi_create_promise(napi_env env,
+                                            napi_deferred* deferred,
+                                            napi_value* promise);
+NAPI_EXTERN napi_status napi_resolve_deferred(napi_env env,
+                                              napi_deferred deferred,
+                                              napi_value resolution);
+NAPI_EXTERN napi_status napi_reject_deferred(napi_env env,
+                                             napi_deferred deferred,
+                                             napi_value rejection);
+NAPI_EXTERN napi_status napi_is_promise(napi_env env,
+                                        napi_value promise,
+                                        bool* is_promise);
+
 EXTERN_C_END
 
 #endif  // SRC_NODE_API_H_