Canvas is not defined

When i try to add filters in the photo using CamanJS in the application it throws canvas is not defined..

<canvas id="demo-image"></canvas>

.ts file code

import 'canvas'
declare let canvas:any;

import {Canvas} from 'canvas';

Caman('#demo-image','#path to the image',function(){
   this.brightness(50);
   this,render(function(){
       alert("Image is Processed");
   });
});

here the camanjs library CamanJS Library anyhelp thanks