diff --git a/IPython/html/static/widgets/js/widget.js b/IPython/html/static/widgets/js/widget.js
index 2431348..315b205 100644
--- a/IPython/html/static/widgets/js/widget.js
+++ b/IPython/html/static/widgets/js/widget.js
@@ -596,10 +596,9 @@ define(["widgets/js/manager",
_.extend(ViewList.prototype, {
initialize: function(create_view, remove_view, context) {
- this.state_change = Promise.resolve();
this._handler_context = context || this;
this._models = [];
- this.views = [];
+ this.views = []; // list of promises for views
this._create_view = create_view;
this._remove_view = remove_view || function(view) {view.remove();};
},
@@ -608,42 +607,36 @@ define(["widgets/js/manager",
/**
* the create_view, remove_view, and context arguments override the defaults
* specified when the list is created.
- * returns a promise that resolves after this update is done
+ * after this function, the .views attribute is a list of promises for views
+ * if you want to perform some action on the list of views, do something like
+ * `Promise.all(myviewlist.views).then(function(views) {...});`
*/
var remove = remove_view || this._remove_view;
var create = create_view || this._create_view;
- if (create === undefined || remove === undefined){
- console.error("Must define a create a remove function");
- }
var context = context || this._handler_context;
- var added_views = [];
- var that = this;
- this.state_change = this.state_change.then(function() {
- var i;
- // first, skip past the beginning of the lists if they are identical
- for (i = 0; i < new_models.length; i++) {
- if (i >= that._models.length || new_models[i] !== that._models[i]) {
- break;
- }
- }
- var first_removed = i;
- // Remove the non-matching items from the old list.
- for (var j = first_removed; j < that._models.length; j++) {
- remove.call(context, that.views[j]);
- }
-
- // Add the rest of the new list items.
- for (; i < new_models.length; i++) {
- added_views.push(create.call(context, new_models[i]));
+ var i = 0;
+ // first, skip past the beginning of the lists if they are identical
+ for (; i < new_models.length; i++) {
+ if (i >= this._models.length || new_models[i] !== this._models[i]) {
+ break;
}
- // make a copy of the input array
- that._models = new_models.slice();
- return Promise.all(added_views).then(function(added) {
- Array.prototype.splice.apply(that.views, [first_removed, that.views.length].concat(added));
- return that.views;
+ }
+
+ var first_removed = i;
+ // Remove the non-matching items from the old list.
+ var removed = this.views.splice(first_removed, this.views.length-first_removed);
+ for (var j = 0; j < removed.length; j++) {
+ removed[j].then(function(view) {
+ remove.call(context, view)
});
- });
- return this.state_change;
+ }
+
+ // Add the rest of the new list items.
+ for (; i < new_models.length; i++) {
+ this.views.push(Promise.resolve(create.call(context, new_models[i])));
+ }
+ // make a copy of the input array
+ this._models = new_models.slice();
},
remove: function() {
@@ -653,14 +646,13 @@ define(["widgets/js/manager",
* returns a promise that resolves after this removal is done
*/
var that = this;
- this.state_change = this.state_change.then(function() {
+ Promise.all(this.views).then(function(views) {
for (var i = 0; i < that.views.length; i++) {
- that._remove_view.call(that._handler_context, that.views[i]);
+ that._remove_view.call(that._handler_context, views[i]);
}
- that._models = [];
that.views = [];
+ that._models = [];
});
- return this.state_change;
},
});