react.js set checkbox's value from state

I have a state called isTeaxher in my react.js application.

I receive data from server and then set it's value :

if(JSON.parse(this.responseText).isTeacher===true || JSON.parse(this.responseText).isTeacher==='true' || JSON.parse(this.responseText).isTeacher==="true")
        that.setState({'isTeacher':'on'});
else
        that.setState({'isTeacher':'off'}); 
console.log(that.state.isTeacher);

console.log() shows value is being changed.

I do this in my componentWillMount function, but the problem is when I render this the checkbox is always unchecked.

Maybe because the is difference between 'on' and "on" and on.

How can I resolve this ?