upgrade vue and assets

assets/src/live.js

@@ -0,0 +1,50 @@
+import {setEcoTimeout} from './utils';
+import Model from './model';
+
+export default class Live {
+    constructor({url,timeout=10,src=""}={}) {
+        this.url = url;
+        this.timeout = timeout;
+        this.src = src;
+
+        this.promise = null;
+        this.items = [];
+    }
+
+    get current() {
+        let item = this.items && this.items[this.items.length-1];
+        if(item)
+            item.src = this.src;
+        return item ? new Model(item) : null;
+    }
+
+    //-- data refreshing
+    drop() {
+        this.promise = null;
+    }
+
+    fetch() {
+        const promise = fetch(this.url).then(response =>
+            response.ok ? response.json()
+                        : Promise.reject(response)
+        ).then(data => {
+            this.items = data;
+            return this.items
+        })
+
+        this.promise = promise;
+        return promise;
+    }
+
+    refresh() {
+        const promise = this.fetch();
+        promise.then(() => {
+            if(promise != this.promise)
+                return [];
+
+            setEcoTimeout(() => this.refresh(), this.timeout*1000)
+        })
+        return promise
+    }
+}
+