| 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/io.js-3.3/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/io.js-3.3/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/io.js-3.3/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/io.js-3.3/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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