init

components/utils/jsping.js

@@ -0,0 +1,24 @@
+function request_image(url) {
+    return new Promise(function(resolve, reject) {
+        var img = new Image();
+        img.onload = function() { resolve(img); };
+        img.onerror = function() { reject(url); };
+        img.src = url + '?random-no-cache=' + Math.floor((1 + Math.random()) * 0x10000).toString(16);
+    });
+}
+
+function ping(url, multiplier) {
+    return new Promise(function(resolve, reject) {
+        var start = (new Date()).getTime();
+        var response = function() { 
+            var delta = ((new Date()).getTime() - start);
+            delta *= (multiplier || 1);
+            resolve(delta); 
+        };
+        request_image(url).then(response).catch(response);
+        
+        setTimeout(function() { reject(Error('Timeout')); }, 5000);
+    });
+}
+
+export default ping;