Add timer to reduce fetch.

static/js/app.js

@@ -1,6 +1,10 @@
+var typingTimer;
+var doneTypingInterval = 500;
+
 var app = new Vue({
     el: '#app',
     data: {
+        prevTerms: '',
         searchTerms: '',
         hits: [],
         new_depicts: [],
@@ -14,8 +18,12 @@ var app = new Vue({
             this.hits = [];
             this.searchTerms = '';
         },
-    search(event) {
+        run_search() {
             var terms = this.searchTerms;
+            if (terms == this.prevTerms) {
+                return;  // no change
+            }
+            this.prevTerms = terms;
             if (terms.length < 3) {
                 this.hits = [];
                 return;
@@ -28,6 +36,10 @@ var app = new Vue({
                 .then((data) => {
                     vm.hits = data.hits;
                 })
+        },
+        search(event) {
+            clearTimeout(typingTimer);
+            typingTimer = setTimeout(this.run_search, doneTypingInterval);
         }
     },
 });