In https://nodejs.org/dist/latest-v9.x/docs/api/n-api.html#n_api_napi_typedarray_type

[out] data: The data buffer underlying the typed array.
[out] byte_offset: The byte offset within the data buffer from which to start projecting the TypedArray.

It seems that the data is started from &data[byte_offset],

but actually in node_api.cc,

if (data != nullptr) {
    *data = static_cast<uint8_t*>(buffer->GetContents().Data()) +
            array->ByteOffset();
}

if (byte_offset != nullptr) {
    *byte_offset = array->ByteOffset();
}

So, the doc should clarify that the out arg data actually points to &data[byte_offset].