rpg-cards/generator/components/card-icon.html

<template id="card-icon">
    <style>
        #icon-container {
            height: 100%;
        }

        svg {
            height: 100%;
        }

        svg path {
            fill: rgb(255, 255, 255);
        }
    </style>

    <div id="icon-container">

    </div>

</template>

<script>
    (function(window, document) {
        var elemName = 'card-icon';
        var mainDoc = document;
        var importDoc = document.currentScript.ownerDocument;

        var proto = Object.create(HTMLElement.prototype);
        proto.loadSvg = function (src, callback) {
            var isLocal = window.location.protocol === 'file:';
            var httpRequest = new XMLHttpRequest();

            httpRequest.onreadystatechange = function () {
                if (httpRequest.readyState === 4) {

                    if (httpRequest.status === 404 || httpRequest.responseXML === null) {
                        throw new Error("Error loading SVG");
                    }

                    if (httpRequest.status === 200 || (isLocal && httpRequest.status === 0)) {
                        if (httpRequest.responseXML instanceof Document) {
                            callback(httpRequest.responseXML.children[0]);
                        }
                    }
                }
            }

            httpRequest.open('GET', src);
            if (httpRequest.overrideMimeType) httpRequest.overrideMimeType('text/xml');
            httpRequest.send();
        }
        Object.defineProperty(proto, "src", {
            get: function() { 
                return "";
            },
            set: function (value) {
                this.setAttribute('src', value);

                var root = this.shadowRoot;
                var container = root.getElementById("icon-container");
                while (container.firstChild) {
                    container.removeChild(container.firstChild);
                }
                this.loadSvg(value, function (svg) {
                    container.appendChild(svg);

                    // game-icons.net specific modifications
                    var firstPath = root.querySelector("svg path");
                    svg.removeChild(firstPath);
                    var secondPath = root.querySelector("svg path");
                    secondPath.style.fill = "";
                });
            }
        });
        proto.createdCallback = function () {
            var template = importDoc.getElementById(elemName);
            var clone = mainDoc.importNode(template.content, true);
            var root = this.createShadowRoot();
            root.appendChild(clone);

            this.src = this.getAttribute('src') || "";
        }
        proto.attributeChangedCallback = function (name, oldValue, newValue) {
            switch (name) {
                case "src": this.src = newValue; break;
            }
        }

        mainDoc.registerElement(elemName, { prototype: proto });

    })(window, document);
</script>