html2canvas/src/svgnodecontainer.js

function SVGNodeContainer(node, native) {
    this.src = node;
    this.image = null;
    var self = this;

    this.promise = native ? new Promise(function(resolve, reject) {
        self.image = new Image();
        self.image.onload = resolve;
        self.image.onerror = reject;
        self.image.src = "data:image/svg+xml," + (new XMLSerializer()).serializeToString(node);
        if (self.image.complete === true) {
            resolve(self.image);
        }
    }) : this.hasFabric().then(function() {
        return new Promise(function(resolve) {
            html2canvas.fabric.parseSVGDocument(node, self.createCanvas.call(self, resolve));
        });
    });
}

SVGNodeContainer.prototype = Object.create(SVGContainer.prototype);