How to make responsive textbox object using fabricjs

Question

I have a textbox object in canvas using fabricjs.

1st scenario:- I wanted to change the Font size of textbox dynamically when we shrink/expand the browser. According to screen size font size should fit to the box so that it should be visible.

2nd scenario:- I wanted to change the Font size of textbox dynamically when we shrink/expand the textbox itself.

var textbox = new fabric.Textbox('Lorum ipsum dolor sit amet', { left: 50, top: 50, width: 150, fontSize: 20 });