nó base64 svg para png
var fabric = require('fabric').fabric;
var canvas = new fabric.createCanvasForNode(100, 100);
var svgStr = '<svg height="100" width="100"><circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" /></svg>';
fabric.loadSVGFromString(svgStr, function(objects, options) {
var obj = new fabric.PathGroup(objects, options);
canvas.add(obj);
console.log('<img src="' + canvas.toDataURL() + '" />');
});
El-Dessouki