In mxml, you have no access to the constructor of the component. Therefore, you have no way of requiring constructor arguments to be set.
I was thinking, it would be nice to have a way to enforce at least that certain properties get set.
So here's my solution. Feel free to improve upon it, it's just the first way I could think of to do this.
First, we add a metadata tag to all required properties of your Component.
[Required] public var requiredArgument:Object;
