1 files changed, 89 insertions, 0 deletions
diff --git a/demo/src/js/lib/sprite.js b/demo/src/js/lib/sprite.js
new file mode 100644
index 00000000..bcd8a0b7
--- /dev/null
+++ b/demo/src/js/lib/sprite.js
@@ -0,0 +1,89 @@
+// ==========================================================================
+// SVG sprite loading and caching
+// This file should be at the top of the body to avoid a flash
+// Usage: loadSprite('https://cdn.com/path/to/sprite.svg', 'sprite-id');
+// The second argument is optional but prevents loading twice
+// ==========================================================================
+
+(function() {
+    window.loadSprite = function(url, id) {
+        if (typeof url !== "string") {
+            return;
+        }
+
+        var body = document.body;
+        var prefix = "cache-";
+        var hasId = typeof id === "string";
+        var isCached = false;
+
+        // Check for *actual* storage support
+        var cacheSupported = (function() {
+            if (!hasId) {
+                return false;
+            }
+            var test = '___test';
+            try {
+                localStorage.setItem(test, test);
+                localStorage.removeItem(test);
+                return true;
+            } catch (e) {
+                return false;
+            }
+        })();
+
+        function updateSprite(container, data) {
+            // Inject content
+            container.innerHTML = data;
+
+            // Inject the SVG to the body
+            body.insertBefore(container, body.childNodes[0]);
+        }
+
+        // Only load once
+        if (!hasId || document.querySelectorAll("#" + id).length === 0) {
+            // Create container
+            var container = document.createElement("div");
+            container.setAttribute("hidden", "");
+
+            if (hasId) {
+                container.setAttribute("id", id);
+            }
+
+            // Check in cache
+            if (cacheSupported) {
+                var cached = localStorage.getItem(prefix + id);
+                isCached = cached !== null;
+
+                if (isCached) {
+                    var data = JSON.parse(cached);
+                    updateSprite(container, data.content);
+                }
+            }
+
+            // ReSharper disable once InconsistentNaming
+            var xhr = new XMLHttpRequest();
+
+            // XHR for Chrome/Firefox/Opera/Safari
+            if ("withCredentials" in xhr) {
+                xhr.open("GET", url, true);
+            }
+            // Not supported
+            else {
+                return;
+            }
+
+            // Once loaded, inject to container and body
+            xhr.onload = function() {
+                if (cacheSupported) {
+                    localStorage.setItem(prefix + id, JSON.stringify({
+                        content: xhr.responseText
+                    }));
+                }
+
+                updateSprite(container, xhr.responseText);
+            };
+
+            xhr.send();
+        }
+    }
+})();