JAVASCRIPT

convert svg to base64 javascript

var s = new XMLSerializer().serializeToString(document.getElementById("svg"))
var encodedData = window.btoa(s);

svg to png base64 javascript

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) {
  // PathGroup changed to Group in newer version
  var obj = new fabric.Group(objects, options);
  canvas.add(obj);            
  console.log('<img src="' + canvas.toDataURL() + '" />');
});