How to manage shadow target of THREE.DirectionalLight

Question

I use three.js rev.76

I don't know how to manage shadow target of THREE.DirectionalLight.

We can set position of DirectionalLight like:

dirLight.position.set(200, 1000, 200 );

But DirectionalLight will look at (0.0.0), and shadow camera too. How i can make it to look at (100.200.300)?