Keep a file locked/checked out for the length of workflow

[tomoconnell]

On creation of a workflow, I want the package node to be locked until the completion of the workflow.
Simply using checkout doesn't help

Anyone done this before?

Edit; sorry forgot to add, preferably using JavaScript

[mitpatoliya]

well you can  have actionevaluator on the edit action so that action will not be visible on the documents which are under workflow.
In the evaluator you can check weather any active workflows associated with this document or not.