From 8a1a5ac42baaca86be4394adc4a9788a6f0cab20 Mon Sep 17 00:00:00 2001
From: Craig Kochis <cjkochis@gmail.com>
Date: Fri, 31 Mar 2023 19:38:08 -0400
Subject: [PATCH] only store changes as revisions

---
 src/libs/revisions.js | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/libs/revisions.js b/src/libs/revisions.js
index 51abcf00..e80c3dce 100644
--- a/src/libs/revisions.js
+++ b/src/libs/revisions.js
@@ -1,3 +1,5 @@
+import {diff} from '@mapbox/mapbox-gl-style-spec'
+
 export class RevisionStore {
   constructor(initialRevisions=[]) {
     this.revisions = initialRevisions
@@ -13,10 +15,17 @@ export class RevisionStore {
   }
 
   addRevision(revision) {
-    //TODO: compare new revision style id with old ones
-    //and ensure that it is always the same id
-    this.revisions.push(revision)
-    this.currentIdx++
+    // only store revision if has changes
+    const changes = diff(revision, this.current);
+    if (changes.length > 0) {
+
+      // clear any "redo" revisions once a change is made
+      // and ensure current index is at end of list
+      this.revisions = this.revisions.slice(0, this.currentIdx + 1);
+
+      this.revisions.push(revision)
+      this.currentIdx++
+    }
   }
 
   undo() {