1## New
2
3NAN provides a `Nan::New()` helper for the creation of new JavaScript objects in a way that's compatible across the supported versions of V8.
4
5 - <a href="#api_nan_new"><b><code>Nan::New()</code></b></a>
6 - <a href="#api_nan_undefined"><b><code>Nan::Undefined()</code></b></a>
7 - <a href="#api_nan_null"><b><code>Nan::Null()</code></b></a>
8 - <a href="#api_nan_true"><b><code>Nan::True()</code></b></a>
9 - <a href="#api_nan_false"><b><code>Nan::False()</code></b></a>
10 - <a href="#api_nan_empty_string"><b><code>Nan::EmptyString()</code></b></a>
11
12
13<a name="api_nan_new"></a>
14### Nan::New()
15
16`Nan::New()` should be used to instantiate new JavaScript objects.
17
18Refer to the specific V8 type in the [V8 documentation](https://v8docs.nodesource.com/node-8.16/d1/d83/classv8_1_1_data.html) for information on the types of arguments required for instantiation.
19
20Signatures:
21
22Return types are mostly omitted from the signatures for simplicity. In most cases the type will be contained within a `v8::Local<T>`. The following types will be contained within a `Nan::MaybeLocal<T>`: `v8::String`, `v8::Date`, `v8::RegExp`, `v8::Script`, `v8::UnboundScript`.
23
24Empty objects:
25
26```c++
27Nan::New<T>();
28```
29
30Generic single and multiple-argument:
31
32```c++
33Nan::New<T>(A0 arg0);
34Nan::New<T>(A0 arg0, A1 arg1);
35Nan::New<T>(A0 arg0, A1 arg1, A2 arg2);
36Nan::New<T>(A0 arg0, A1 arg1, A2 arg2, A3 arg3);
37```
38
39For creating `v8::FunctionTemplate` and `v8::Function` objects:
40
41_The definition of `Nan::FunctionCallback` can be found in the [Method declaration](./methods.md#api_nan_method) documentation._
42
43```c++
44Nan::New<T>(Nan::FunctionCallback callback,
45            v8::Local<v8::Value> data = v8::Local<v8::Value>());
46Nan::New<T>(Nan::FunctionCallback callback,
47            v8::Local<v8::Value> data = v8::Local<v8::Value>(),
48            A2 a2 = A2());
49```
50
51Native number types:
52
53```c++
54v8::Local<v8::Boolean> Nan::New<T>(bool value);
55v8::Local<v8::Int32> Nan::New<T>(int32_t value);
56v8::Local<v8::Uint32> Nan::New<T>(uint32_t value);
57v8::Local<v8::Number> Nan::New<T>(double value);
58```
59
60String types:
61
62```c++
63Nan::MaybeLocal<v8::String> Nan::New<T>(std::string const& value);
64Nan::MaybeLocal<v8::String> Nan::New<T>(const char * value, int length);
65Nan::MaybeLocal<v8::String> Nan::New<T>(const char * value);
66Nan::MaybeLocal<v8::String> Nan::New<T>(const uint16_t * value);
67Nan::MaybeLocal<v8::String> Nan::New<T>(const uint16_t * value, int length);
68```
69
70Specialized types:
71
72```c++
73v8::Local<v8::String> Nan::New<T>(v8::String::ExternalStringResource * value);
74v8::Local<v8::String> Nan::New<T>(Nan::ExternalOneByteStringResource * value);
75v8::Local<v8::RegExp> Nan::New<T>(v8::Local<v8::String> pattern, v8::RegExp::Flags flags);
76```
77
78Note that `Nan::ExternalOneByteStringResource` maps to [`v8::String::ExternalOneByteStringResource`](https://v8docs.nodesource.com/node-8.16/d9/db3/classv8_1_1_string_1_1_external_one_byte_string_resource.html), and `v8::String::ExternalAsciiStringResource` in older versions of V8.
79
80
81<a name="api_nan_undefined"></a>
82### Nan::Undefined()
83
84A helper method to reference the `v8::Undefined` object in a way that is compatible across all supported versions of V8.
85
86Signature:
87
88```c++
89v8::Local<v8::Primitive> Nan::Undefined()
90```
91
92<a name="api_nan_null"></a>
93### Nan::Null()
94
95A helper method to reference the `v8::Null` object in a way that is compatible across all supported versions of V8.
96
97Signature:
98
99```c++
100v8::Local<v8::Primitive> Nan::Null()
101```
102
103<a name="api_nan_true"></a>
104### Nan::True()
105
106A helper method to reference the `v8::Boolean` object representing the `true` value in a way that is compatible across all supported versions of V8.
107
108Signature:
109
110```c++
111v8::Local<v8::Boolean> Nan::True()
112```
113
114<a name="api_nan_false"></a>
115### Nan::False()
116
117A helper method to reference the `v8::Boolean` object representing the `false` value in a way that is compatible across all supported versions of V8.
118
119Signature:
120
121```c++
122v8::Local<v8::Boolean> Nan::False()
123```
124
125<a name="api_nan_empty_string"></a>
126### Nan::EmptyString()
127
128Call [`v8::String::Empty`](https://v8docs.nodesource.com/node-8.16/d2/db3/classv8_1_1_string.html#a7c1bc8886115d7ee46f1d571dd6ebc6d) to reference the empty string in a way that is compatible across all supported versions of V8.
129
130Signature:
131
132```c++
133v8::Local<v8::String> Nan::EmptyString()
134```
135
136
137<a name="api_nan_new_one_byte_string"></a>
138### Nan::NewOneByteString()
139
140An implementation of [`v8::String::NewFromOneByte()`](https://v8docs.nodesource.com/node-8.16/d2/db3/classv8_1_1_string.html#a5264d50b96d2c896ce525a734dc10f09) provided for consistent availability and API across supported versions of V8. Allocates a new string from Latin-1 data.
141
142Signature:
143
144```c++
145Nan::MaybeLocal<v8::String> Nan::NewOneByteString(const uint8_t * value,
146                                                  int length = -1)
147```
148