Add an arrow on the line

[MichelleCLiao]

How to add an arrow on the line?
I'm having a issue that I would like to paint a line in between of two path() objects and add an arrow at the end of the line indicates that one object points to the other. But I find no where on the manual script telling how to add the arrow. Can anybody help me on this?
Thanks in advance!

[Shestac92]

@MichelleCLiao
The GraphicsJS provides only some primitives to help to implement drawing functions, but many special signs, symbols, etc should be implemented manually using these primitives or paths.
So, the arrow of any rotation angle can be implemented manually by a path with fill.
For horizontal or vertical arrow you can use triangle primitives.