Chart js is not working

Hello campers ,I followed the Chart js docs ,wich explain how to use it with webpack in Chart integration section ,
but when I run webpack the canvas element changes but it is not displayed , it is like full of the bar chart but it is not visible ,I typed on the top of index.js wich is the entry file this
import Chart from ‘chart.js’;
and in it I used some of the provided example of creating bar chart.
and also I cretaed canvas tag in html page,so it seems like everything is good,but something is missing I don’t know what it is .
please any help is apperciated .