Listeners on data-change events may not be called if the property is bound #3077
Assignees
Labels
Comments
|
👍 We have this exact issue. I believe #2815 is related to this. Modifying the Polymer build and setting |
sorvell
pushed a commit
that referenced
this issue
Nov 30, 2015
Revert fromAbove in applyEffectValue. Add test. Fixes #3077.
kevinpschaaf
added a commit
that referenced
this issue
Jan 20, 2017
…4262. * `Polymer.Settings.suppressTemplateNotifications `- disables `dom-change` and `rendered-item-count` events from `dom-if`, `dom-repeat`, and `don-bind`. Users can opt back into `dom-change` events by setting the `notify-dom-change` attribute (`notifyDomChange: true` property) to `dom-if`/`don-repeat` instances. * `Polymer.Settings.suppressBindingNotifications` - disables notify effects when propagating data downward via bindings. Generally these are never useful unless users are explicitly doing something like `<my-el foo="{{foo}} on-foo-changed="{{handleFoo}}">` or calling `addEventListener('foo-changed', ...)` on an element where `foo` is bound (we attempted to make this the default some time back but needed to revert it when we found via #3077 that users were indeed doing this). Users that avoid these patterns can enjoy the potentially significant benefit of suppressing unnecessary events during downward data flow by opting into this flag.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
We recently changed property sets at bind data propagation so that they avoid firing data change events. This was done as an optimization: these events are only necessary for 2-way binding and if the value is being sent from the bindor, then no notification is necessary. The problem is that users who have added event listeners for data change events (e.g.
foo-change) will not be notified when the property changes due to binding. We may need to consider backing this optimization out.The text was updated successfully, but these errors were encountered: