Fix dragging multiple anchors of a polyline object

CHANGELOG.md

@@ -7,6 +7,11 @@ To see every change with descriptions aimed at developers, see
 As a continuously updated web app, Cocreate uses dates
 instead of version numbers.
 
+## 2023-11-01
+
+* Fix dragging multiple anchors of a polyline object
+  [[#226](https://github.com/edemaine/cocreate/issues/226)]
+
 ## 2023-08-09
 
 * New polygonal line tool!

client/Anchor.coffee

@@ -33,6 +33,9 @@ export anchorsOf = (obj) ->
     y: y + ty
 
 pointMove = (obj, moved, index, coords) ->
+  old = moved[index] ? obj.pts[index]
+  if old?
+    console.log old.x, old.y, 'vs', coords.x, coords.y
   if (old = moved[index] ? obj.pts[index])? and
      old.x == coords.x and old.y == coords.y
     false

client/tools/modes.coffee

@@ -349,9 +349,11 @@ defineTool
           h.moved[id] ?= {}
           moved = false
           for index in anchorSelection.indicesForId id
-            x = obj.anchors[index].x + motion.x
-            y = obj.anchors[index].y + motion.y
-            moved or= anchorMove obj, h.moved[id], index, {x, y}
+            # Can't write `moved or=` because we don't want to short-circuit
+            if anchorMove obj, h.moved[id], index,
+              x: obj.anchors[index].x + motion.x
+              y: obj.anchors[index].y + motion.y
+            then moved = true
           continue unless moved
           diffs[id] = {id, pts: h.moved[id]}
         h.edit diffs if (id for id of diffs).length