1 | ## Miscellaneous V8 Helpers
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2 |
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3 | - <a href="#api_nan_utf8_string"><b><code>Nan::Utf8String</code></b></a>
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4 | - <a href="#api_nan_get_current_context"><b><code>Nan::GetCurrentContext()</code></b></a>
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5 | - <a href="#api_nan_set_isolate_data"><b><code>Nan::SetIsolateData()</code></b></a>
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6 | - <a href="#api_nan_get_isolate_data"><b><code>Nan::GetIsolateData()</code></b></a>
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7 | - <a href="#api_nan_typedarray_contents"><b><code>Nan::TypedArrayContents</code></b></a>
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8 |
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9 |
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10 | <a name="api_nan_utf8_string"></a>
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11 | ### Nan::Utf8String
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12 |
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13 | Converts an object to a UTF-8-encoded character array. If conversion to a string fails (e.g. due to an exception in the toString() method of the object) then the length() method returns 0 and the * operator returns NULL. The underlying memory used for this object is managed by the object.
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14 |
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15 | An implementation of [`v8::String::Utf8Value`](https://v8docs.nodesource.com/node-8.11/d4/d1b/classv8_1_1_string_1_1_utf8_value.html) that is consistent across all supported versions of V8.
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16 |
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17 | Definition:
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18 |
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19 | ```c++
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20 | class Nan::Utf8String {
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21 | public:
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22 | Nan::Utf8String(v8::Local<v8::Value> from);
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23 |
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24 | int length() const;
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25 |
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26 | char* operator*();
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27 | const char* operator*() const;
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28 | };
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29 | ```
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30 |
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31 | <a name="api_nan_get_current_context"></a>
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32 | ### Nan::GetCurrentContext()
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33 |
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34 | A call to [`v8::Isolate::GetCurrent()->GetCurrentContext()`](https://v8docs.nodesource.com/node-8.11/d5/dda/classv8_1_1_isolate.html#a81c7a1ed7001ae2a65e89107f75fd053) that works across all supported versions of V8.
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35 |
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36 | Signature:
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37 |
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38 | ```c++
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39 | v8::Local<v8::Context> Nan::GetCurrentContext()
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40 | ```
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41 |
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42 | <a name="api_nan_set_isolate_data"></a>
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43 | ### Nan::SetIsolateData()
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44 |
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45 | A helper to provide a consistent API to [`v8::Isolate#SetData()`](https://v8docs.nodesource.com/node-8.11/d5/dda/classv8_1_1_isolate.html#a7acadfe7965997e9c386a05f098fbe36).
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46 |
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47 | Signature:
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48 |
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49 | ```c++
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50 | void Nan::SetIsolateData(v8::Isolate *isolate, T *data)
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51 | ```
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52 |
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53 |
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54 | <a name="api_nan_get_isolate_data"></a>
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55 | ### Nan::GetIsolateData()
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56 |
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57 | A helper to provide a consistent API to [`v8::Isolate#GetData()`](https://v8docs.nodesource.com/node-8.11/d5/dda/classv8_1_1_isolate.html#aabd223436bc1100a787dadaa024c6257).
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58 |
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59 | Signature:
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60 |
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61 | ```c++
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62 | T *Nan::GetIsolateData(v8::Isolate *isolate)
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63 | ```
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64 |
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65 | <a name="api_nan_typedarray_contents"></a>
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66 | ### Nan::TypedArrayContents<T>
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67 |
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68 | A helper class for accessing the contents of an ArrayBufferView (aka a typedarray) from C++. If the input array is not a valid typedarray, then the data pointer of TypedArrayContents will default to `NULL` and the length will be 0. If the data pointer is not compatible with the alignment requirements of type, an assertion error will fail.
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69 |
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70 | Note that you must store a reference to the `array` object while you are accessing its contents.
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71 |
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72 | Definition:
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73 |
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74 | ```c++
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75 | template<typename T>
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76 | class Nan::TypedArrayContents {
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77 | public:
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78 | TypedArrayContents(v8::Local<Value> array);
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79 |
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80 | size_t length() const;
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81 |
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82 | T* const operator*();
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83 | const T* const operator*() const;
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84 | };
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85 | ```
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