script.js

var resizedCanvas = document.createElement("canvas");
var resizedContext = resizedCanvas.getContext("2d");

resizedCanvas.width = "1080";
resizedCanvas.height = "1920";

var canvas = $('canvas')[0];
var context = canvas.getContext("2d");

resizedContext.drawImage(canvas, 0, 0, resizedCanvas.width, resizedCanvas.height);
var myResizedData = resizedCanvas.toDataURL();

var fb = firebase.database().ref().child('filter').push({
    image: myResizedData
});

window._pjscMeta.scriptOutput = {
    test: 'test'
};