From eb9ea0cbcab418628966b003f74e7b4f2e63fb67 Mon Sep 17 00:00:00 2001
From: carson <carson@leaddyno.com>
Date: Tue, 5 May 2020 02:59:48 -0700
Subject: [PATCH] load content from server on history cache miss

---
 TODO.md     | 11 ++++++-----
 src/htmx.js | 27 ++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/TODO.md b/TODO.md
index 24b45771..38aa6d37 100644
--- a/TODO.md
+++ b/TODO.md
@@ -12,10 +12,12 @@
 
 ## TODOS
 
-* history support
-  * Implement LRU
-  * Issue GET to restore content if there isn't a copy locally
-* polling cancellation API 
+* settle formalization
+  * focus recapture
+* polling cancellation API 205 code
+* meta config tag
+* simple logging API
+
 * Testing
   * polling
   * merge
@@ -23,7 +25,6 @@
   * history
   * hx-boost
   * transition model for content swaps
-* distribute on https://unpkg.com/
 * build website with 11ty
   * landing page
   * docs page 
diff --git a/src/htmx.js b/src/htmx.js
index d8cecea9..39d9b791 100644
--- a/src/htmx.js
+++ b/src/htmx.js
@@ -584,8 +584,8 @@ var HTMx = HTMx || (function () {
         // History Support
         //====================================================================
         function getHistoryElement() {
-            var historyElt = getDocument().getElementsByClassName('hx-history-element');
-            return historyElt.length > 0 ? historyElt[0] : getDocument().body;
+            var historyElt = getDocument().querySelector('.hx-history-element');
+            return historyElt || getDocument().body;
         }
 
         function purgeOldestPaths(paths, historyTimestamps) {
@@ -628,13 +628,30 @@ var HTMx = HTMx || (function () {
             }
         }
 
+        function loadHistoryFromServer(pathAndSearch) {
+            triggerEvent(getDocument().body, "historyCacheMiss.hx", {path: pathAndSearch});
+            var request = new XMLHttpRequest();
+            request.open('GET', pathAndSearch, true);
+            request.onload = function () {
+                triggerEvent(getDocument().body, "historyCacheMissLoad.hx", {path: pathAndSearch});
+                if (this.status >= 200 && this.status < 400) {
+                    var fragment = makeFragment(this.response);
+                    fragment = fragment.querySelector('.hx-history-element') || fragment;
+                    swapInnerHTML(getHistoryElement(), fragment);
+                }
+            };
+        }
+
         function restoreHistory() {
             var pathAndSearch = location.pathname+location.search;
             triggerEvent(getDocument().body, "historyUpdate.hx", {path:pathAndSearch});
-            bumpHistoryAccessDate(pathAndSearch);
             var content = localStorage.getItem('hx-history-content-' + pathAndSearch);
-            var elt = getHistoryElement();
-            swapInnerHTML(elt, makeFragment(content));
+            if (content) {
+                bumpHistoryAccessDate(pathAndSearch);
+                swapInnerHTML(getHistoryElement(), makeFragment(content));
+            } else {
+                loadHistoryFromServer(pathAndSearch);
+            }
         }
 
         function shouldPush(elt) {