UNPKG

2.63 kBMarkdownView Raw
1## Nan::Callback
2
3`Nan::Callback` makes it easier to use `v8::Function` handles as callbacks. A class that wraps a `v8::Function` handle, protecting it from garbage collection and making it particularly useful for storage and use across asynchronous execution.
4
5 - <a href="#api_nan_callback"><b><code>Nan::Callback</code></b></a>
6
7<a name="api_nan_callback"></a>
8### Nan::Callback
9
10```c++
11class Callback {
12 public:
13 Callback();
14
15 explicit Callback(const v8::Local<v8::Function> &fn);
16
17 ~Callback();
18
19 bool operator==(const Callback &other) const;
20
21 bool operator!=(const Callback &other) const;
22
23 v8::Local<v8::Function> operator*() const;
24
25 MaybeLocal<v8::Value> operator()(AsyncResource* async_resource,
26 v8::Local<v8::Object> target,
27 int argc = 0,
28 v8::Local<v8::Value> argv[] = 0) const;
29
30 MaybeLocal<v8::Value> operator()(AsyncResource* async_resource,
31 int argc = 0,
32 v8::Local<v8::Value> argv[] = 0) const;
33
34 void SetFunction(const v8::Local<v8::Function> &fn);
35
36 v8::Local<v8::Function> GetFunction() const;
37
38 bool IsEmpty() const;
39
40 void Reset(const v8::Local<v8::Function> &fn);
41
42 void Reset();
43
44 MaybeLocal<v8::Value> Call(v8::Local<v8::Object> target,
45 int argc,
46 v8::Local<v8::Value> argv[],
47 AsyncResource* async_resource) const;
48 MaybeLocal<v8::Value> Call(int argc,
49 v8::Local<v8::Value> argv[],
50 AsyncResource* async_resource) const;
51
52 // Deprecated versions. Use the versions that accept an async_resource instead
53 // as they run the callback in the correct async context as specified by the
54 // resource. If you want to call a synchronous JS function (i.e. on a
55 // non-empty JS stack), you can use Nan::Call instead.
56 v8::Local<v8::Value> operator()(v8::Local<v8::Object> target,
57 int argc = 0,
58 v8::Local<v8::Value> argv[] = 0) const;
59
60 v8::Local<v8::Value> operator()(int argc = 0,
61 v8::Local<v8::Value> argv[] = 0) const;
62 v8::Local<v8::Value> Call(v8::Local<v8::Object> target,
63 int argc,
64 v8::Local<v8::Value> argv[]) const;
65
66 v8::Local<v8::Value> Call(int argc, v8::Local<v8::Value> argv[]) const;
67};
68```
69
70Example usage:
71
72```c++
73v8::Local<v8::Function> function;
74Nan::Callback callback(function);
75callback.Call(0, 0);
76```