Intent to Implement and Ship: addEventListener AddEventListenerOptions API

[Dave Tapuska]

Contact emails dtap...@chromium.org Spec https://dom.spec.whatwg.org/#dom-eventtarget-addeventlistener Summary EventListenerOptions API was added in https://www.chromestatus.com/features/5718574840676352 The spec was revised to add AddEventListenerOptions which is a dictionary only for addEventListener(...) so that fields could be added that did not make up the matching key. Where the matching key semantics are used for detecting duplicate adds and removal. This change is to move the add the AddEventListenerOptions dictionary definition, change the API and move the 'passive' field from EventListenerOptions to AddEventListenerOptions

This change does NOT add or implement the 'once' field in the AddEventListenerOptions dictionary. Motivation Make the key behaviour on addEventListener explicit. In the original spec it was a little undefined what it should actually match if the UA didn't support the dictionary parameters. Interoperability risk Firefox: Public support Edge: Public support Safari: No public signals Web developers: No signals Compatibility risk Minor API change. Some slight difference in the semantics of a second call to addEventListener.

The dictionary itself is not observable to JavaScript. The main change is the semantics of remove. In M51; addEventListener('touchstart', func, {passive: true}); addEventListener('touchstart', func, {passive: false}); would end up adding two listeners. But since passive is no longer part of the key; as proposed in M52; the second add will be a no-op. The key is made up of only 3 args; eventtype, listener function, capture. Ongoing technical constraints None

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes or no. Yes OWP launch tracking bug https://crbug.com/602735 Link to entry on the Chrome Platform Status https://www.chromestatus.com/features/6540125429301248 Requesting approval to ship?

Yes

[Philip Jägenstedt]

LGTM1

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[Chris Harrelson]

LGTM2

[Dimitri Glazkov]

LGTM3