More TypedArray helpers?

Right now in node-canvas we've got stuff like this:

#if NODE_MAJOR_VERSION == 0 && NODE_MINOR_VERSION <= 10
    Local<Int32> sizeHandle = Nan::New(length);
    Local<Value> caargv[] = { sizeHandle };
    clampedArray = global->Get(Nan::New("Uint8ClampedArray").ToLocalChecked()).As<Function>()->NewInstance(1, caargv);
#else
    clampedArray = Uint8ClampedArray::New(ArrayBuffer::New(Isolate::GetCurrent(), length), 0, length);
#endif

and this:

#if NODE_MAJOR_VERSION == 0 && NODE_MINOR_VERSION <= 10
 if (info[0]->ToObject()->GetIndexedPropertiesExternalArrayDataType() == kExternalPixelArray) {
    clampedArray = info[0]->ToObject();
    length = clampedArray->GetIndexedPropertiesExternalArrayDataLength();
#else
 if (info[0]->IsUint8ClampedArray() && info[1]->IsUint32()) {
    clampedArray = info[0].As<Uint8ClampedArray>();
    length = clampedArray->Length();
#endif

Since TypedArrayContents was added (thank you!), wondering if there's interest in adding more helpers for TypedArrays? Maybe something like:

• Nan::New<TypedArrayT>(Nan::New<ArrayBuffer>(byteLength[, offset[, length]]))
• Nan::New<TypedArrayT>(length)

Not so sure on argument testing. It would be nice if NAN_METHOD unified the interface so info[x]->IsUint8Array() (edit: and all the other TypedArray types) just worked. Otherwise is the only option Nan::IsUint8ClampedArray, Nan::IsUint8Array, ... and Nan::TypedArrayLength(TypedArray) ?

Start by reviewing the existing TypedArrayContents helper and the linked Nan pull request 486, then compare the TypedArray usage shown from src/ImageData.cc. The issue is complete only when the desired constructor, type-checking, and length-helper API are agreed and implemented with corresponding coverage; the payload does not name test files.