From 436cd166747b4712fd56d456503b49da560f2099 Mon Sep 17 00:00:00 2001
From: Roman Karpov <roman.karpov@gmail.com>
Date: Thu, 13 May 2021 11:38:18 +0300
Subject: [PATCH] feat (individual presenter): add support for external .html
 templates

---
 source-web/js/common/backend.js | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/source-web/js/common/backend.js b/source-web/js/common/backend.js
index ff3a47be3..47ce3e2c2 100644
--- a/source-web/js/common/backend.js
+++ b/source-web/js/common/backend.js
@@ -892,7 +892,21 @@ browserBackend.uploadFile = function (params, tries) {
   });
 };
 
-browserBackend.loadFile = function (url) {
+const memoize = (fn) => {
+  const cache = {};
+  return (...args) => {
+    const n = args[0];
+    if (n in cache) {
+      return cache[n];
+    } else {
+      const result = fn(n);
+      cache[n] = result;
+      return result;
+    }
+  };
+};
+
+browserBackend.loadFile = memoize(function (url) {
   return new Promise(function (resolve, reject) {
     const done = () => {
       if (xhr.status === 200) {
@@ -913,7 +927,7 @@ browserBackend.loadFile = function (url) {
     xhr.ontimeout = fail;
     xhr.send();
   });
-};
+});
 
 // //////////////////////////////////////////////////////////////////////