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You are reading a draft of the next documentation and it's in continuos update so if you don't find what you need please refer to: C++ wrapper classes for the ABI-stable C APIs for Node.js

Promise

The Promise class, along with its Promise::Deferred class, implement the ability to create, resolve, and reject Promise objects.

The basic approach is to create a Promise::Deferred object and return to your caller the value returned by the Promise::Deferred::Promise method. For example:

Value YourFunction(const CallbackInfo& info) {
  // your code goes here...
  Promise::Deferred deferred = Promise::Deferred::New(info.Env());
  // deferred needs to survive this call...
  return deferred.Promise();
}

Later, when the asynchronous process completes, call either the Resolve or Reject method on the Promise::Deferred object created earlier:

  deferred.Resolve(String::New(info.Env(), "OK"));

Promise::Deferred Methods

Factory Method

static Promise::Deferred Promise::Deferred::New(napi_env env);
  • [in] env: The napi_env environment in which to create the Deferred object.

Constructor

Promise::Deferred(napi_env env);
  • [in] env: The napi_env environment in which to construct the Deferred object.

Promise

Promise Promise::Deferred::Promise() const;

Returns the Promise object held by the Promise::Deferred object.

Resolve

void Promise::Deferred::Resolve(napi_value value) const;

Resolves the Promise object held by the Promise::Deferred object.

  • [in] value: The N-API primitive value with which to resolve the Promise.

Reject

void Promise::Deferred::Reject(napi_value value) const;

Rejects the Promise object held by the Promise::Deferred object.

  • [in] value: The N-API primitive value with which to reject the Promise.