ShareJS and Codemirror doubt

[Afua Kwafo-Awua]

Hi everyone. I'm really new to ShareJs and I was following a tutorial to create a collaborative editor app with Codemirror, using the Share-codemirror app. 

My question is, how to start with a document that already has text on it? Because it always start with a blank editor and I want to start with an editor with initial code inside.

I hope someone can help me! Thank you