JavascriptCore ArrayBuffer from Data

gistfile1.txt

// allocate a pointer to hold contents
let ptr: UnsafeMutableBufferPointer<UInt8> = UnsafeMutableBufferPointer<UInt8>.allocate(capacity: contents!.count)

// copy Data into ptr
contents?.withUnsafeBytes { (contentsPtr: UnsafePointer<UInt8>) -> Void in
    let _ = ptr.initialize(from: UnsafeBufferPointer(start: contentsPtr, count: contents!.count))
}

var exception : JSValueRef?
let deallocator: JSTypedArrayBytesDeallocator = { ptr, deallocatorContext in
    // deallocate previous allocated ptr.
    ptr?.deallocate()
}

let arrayBufferRef = JSObjectMakeArrayBufferWithBytesNoCopy(
    ctx.jsGlobalContextRef,
    ptr.baseAddress,
    contents!.count,
    deallocator,
    nil,
    &exception)

if exception != nil {
    ctx.exception = JSValue(jsValueRef: exception, in: ctx)
    return nil
}

return JSValue(jsValueRef: arrayBufferRef, in: ctx)