From 0dd262d1dde6bf1e628ea503230fb457d61e2160 Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Fri, 12 Apr 2019 09:56:18 -0400
Subject: [PATCH] Don't dispatch 'change' on `history.merged`, dispatch 'merge'
 only

Change performs an expensive immediate redraw, and merge can schedule
a redraw for later.
---
 modules/core/history.js   |  1 -
 modules/renderer/map.js   |  1 +
 test/spec/core/history.js | 10 +++++-----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/modules/core/history.js b/modules/core/history.js
index f634758ad..ef633ae33 100644
--- a/modules/core/history.js
+++ b/modules/core/history.js
@@ -123,7 +123,6 @@ export function coreHistory(context) {
             _stack[0].graph.rebase(entities, stack, false);
             _tree.rebase(entities, false);
 
-            dispatch.call('change', this, undefined, extent);
             dispatch.call('merge', this, entities);
         },
 
diff --git a/modules/renderer/map.js b/modules/renderer/map.js
index 7b1ec28b6..1fdf0d04a 100644
--- a/modules/renderer/map.js
+++ b/modules/renderer/map.js
@@ -112,6 +112,7 @@ export function rendererMap(context) {
         }
 
         context.history()
+            .on('merge.map', function() { scheduleRedraw(); })
             .on('change.map', immediateRedraw)
             .on('undone.map', function(stack, fromStack) {
                 didUndoOrRedo(stack, fromStack.transform);
diff --git a/test/spec/core/history.js b/test/spec/core/history.js
index 26cb5a5b0..d355961f7 100644
--- a/test/spec/core/history.js
+++ b/test/spec/core/history.js
@@ -28,11 +28,11 @@ describe('iD.coreHistory', function () {
             expect(history.graph().entity('n')).to.equal(n);
         });
 
-        it('emits a change event with the specified extent', function () {
-            var extent = {};
-            history.on('change', spy);
-            history.merge([], extent);
-            expect(spy).to.have.been.calledWith(undefined, extent);
+        it('emits a merge event with the new entities', function () {
+            var n = iD.osmNode({id: 'n'});
+            history.on('merge', spy);
+            history.merge([n]);
+            expect(spy).to.have.been.calledWith([n]);
         });
     });