From 0ea69548ea6389d8c3020939aed4fd2dd6bddfdf Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Tue, 5 Mar 2019 17:46:54 -0500
Subject: [PATCH] Add history.pauseChangeDispatch /
 history.resumeChangeDispatch To avoid dispatching change events at improper
 times

---
 modules/core/history.js   | 25 ++++++++++++++++----
 test/spec/core/history.js | 49 +++++++++++++++++++++++++++++----------
 2 files changed, 57 insertions(+), 17 deletions(-)

diff --git a/modules/core/history.js b/modules/core/history.js
index 97f730579..fb7f9fa8c 100644
--- a/modules/core/history.js
+++ b/modules/core/history.js
@@ -36,6 +36,7 @@ export function coreHistory(context) {
     var duration = 150;
     var _imageryUsed = [];
     var _checkpoints = {};
+    var _pausedGraph;
     var _stack;
     var _index;
     var _tree;
@@ -104,11 +105,13 @@ export function coreHistory(context) {
     // determine difference and dispatch a change event
     function change(previous, isAnnotated) {
         var difference = coreDifference(previous, history.graph());
-        dispatch.call('change', this, difference);
-        if (isAnnotated) {
-            // actions like dragging a node can fire lots of changes,
-            // so use 'annotatedChange' to listen for grouped undo/redo changes
-            dispatch.call('annotatedChange', this, difference);
+        if (!_pausedGraph) {
+            dispatch.call('change', this, difference);
+            if (isAnnotated) {
+                // actions like dragging a node can fire lots of changes,
+                // so use 'annotatedChange' to listen for grouped undo/redo changes
+                dispatch.call('annotatedChange', this, difference);
+            }
         }
         return difference;
     }
@@ -244,6 +247,18 @@ export function coreHistory(context) {
         },
 
 
+        pauseChangeDispatch: function() {
+            _pausedGraph = _stack[_index].graph;
+        },
+
+
+        resumeChangeDispatch: function() {
+            var previous = _pausedGraph;
+            _pausedGraph = null;
+            return change(previous, true);
+        },
+
+
         undoAnnotation: function() {
             var i = _index;
             while (i >= 0) {
diff --git a/test/spec/core/history.js b/test/spec/core/history.js
index 3c1533d3b..c9872a66f 100644
--- a/test/spec/core/history.js
+++ b/test/spec/core/history.js
@@ -55,8 +55,8 @@ describe('iD.History', function () {
         });
 
         it('performs multiple actions', function () {
-            var action1 = sinon.stub().returns(iD.coreGraph()),
-                action2 = sinon.stub().returns(iD.coreGraph());
+            var action1 = sinon.stub().returns(iD.coreGraph());
+            var action2 = sinon.stub().returns(iD.coreGraph());
             history.perform(action1, action2, 'annotation');
             expect(action1).to.have.been.called;
             expect(action2).to.have.been.called;
@@ -99,8 +99,8 @@ describe('iD.History', function () {
         });
 
         it('performs multiple actions', function () {
-            var action1 = sinon.stub().returns(iD.coreGraph()),
-                action2 = sinon.stub().returns(iD.coreGraph());
+            var action1 = sinon.stub().returns(iD.coreGraph());
+            var action2 = sinon.stub().returns(iD.coreGraph());
             history.replace(action1, action2, 'annotation');
             expect(action1).to.have.been.called;
             expect(action2).to.have.been.called;
@@ -193,8 +193,8 @@ describe('iD.History', function () {
         });
 
         it('performs multiple actions', function () {
-            var action1 = sinon.stub().returns(iD.coreGraph()),
-                action2 = sinon.stub().returns(iD.coreGraph());
+            var action1 = sinon.stub().returns(iD.coreGraph());
+            var action2 = sinon.stub().returns(iD.coreGraph());
             history.perform(action, 'annotation');
             history.overwrite(action1, action2, 'annotation2');
             expect(action1).to.have.been.called;
@@ -266,6 +266,31 @@ describe('iD.History', function () {
         });
     });
 
+    describe('#pauseChangeDispatch / #resumeChangeDispatch', function() {
+        it('prevents change events from getting dispatched', function() {
+            history.perform(action, 'base');
+            history.on('change', spy);
+
+            history.pauseChangeDispatch();
+
+            history.perform(action, 'perform');
+            expect(spy).to.have.been.notCalled;
+            history.replace(action, 'replace');
+            expect(spy).to.have.been.notCalled;
+            history.overwrite(action, 'replace');
+            expect(spy).to.have.been.notCalled;
+            history.undo();
+            expect(spy).to.have.been.notCalled;
+            history.redo();
+            expect(spy).to.have.been.notCalled;
+            history.pop();
+            expect(spy).to.have.been.notCalled;
+
+            var difference = history.resumeChangeDispatch();
+            expect(spy).to.have.been.calledOnceWith(difference);
+        });
+    });
+
     describe('#changes', function () {
         it('includes created entities', function () {
             var node = iD.osmNode();
@@ -274,8 +299,8 @@ describe('iD.History', function () {
         });
 
         it('includes modified entities', function () {
-            var node1 = iD.osmNode({id: 'n1'}),
-                node2 = node1.update({ tags: { yes: 'no' } });
+            var node1 = iD.osmNode({id: 'n1'});
+            var node2 = node1.update({ tags: { yes: 'no' } });
             history.merge([node1]);
             history.perform(function (graph) { return graph.replace(node2); });
             expect(history.changes().modified).to.eql([node2]);
@@ -357,10 +382,10 @@ describe('iD.History', function () {
         });
 
         it('generates v3 JSON', function() {
-            var node_1 = iD.osmNode({id: 'n-1'}),
-                node1 = iD.osmNode({id: 'n1'}),
-                node2 = iD.osmNode({id: 'n2'}),
-                node3 = iD.osmNode({id: 'n3'});
+            var node_1 = iD.osmNode({id: 'n-1'});
+            var node1 = iD.osmNode({id: 'n1'});
+            var node2 = iD.osmNode({id: 'n2'});
+            var node3 = iD.osmNode({id: 'n3'});
             history.merge([node1, node2, node3]);
             history.perform(iD.actionAddEntity(node_1));           // addition
             history.perform(iD.actionChangeTags('n2', {k: 'v'}));  // modification