TouchEvent is not always defined
Categories
(Core :: DOM: Events, defect, P3)
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People
(Reporter: aritz, Unassigned)
References
Details
User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:85.0) Gecko/20100101 Firefox/85.0
Steps to reproduce:
Attempt to use code using ev instanceof TouchEvent
Actual results:
If the system doesn't have a touch device when the page is loaded, and touch simulation isn't enabled, "ReferenceError: TouchEvent is not defined" is thrown.
Expected results:
TouchEvent should always be defined, instead of only when touch simulation is enabled or a touch device is detected. This is the current behaviour on Chromium.
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Updated•3 years ago
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Comment 1•3 years ago
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Did you file an equivalent bug against Safari? It's not clear to me what should happen here as Chrome does throw for document.createEvent("touchevent") on desktop.
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Comment 2•3 years ago
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We could in theory set the pref to 1, I think
https://searchfox.org/mozilla-central/rev/3f97afc8db535f9b0232222cb48cc4cbf8334c76/modules/libpref/init/StaticPrefList.yaml#3364
The legacy APIs are controlled by a different pref
https://searchfox.org/mozilla-central/rev/3f97afc8db535f9b0232222cb48cc4cbf8334c76/modules/libpref/init/StaticPrefList.yaml#3355-3361
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Comment 3•3 years ago
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But it isn't clear to me why Chrome's behavior would be correct. At least it breaks various feature testing mechanisms.
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Comment 4•2 years ago
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Given the discussion in bug 1412485 (in particular comment 1 there) it seems like it was somewhat intentional. Hide the "legacy APIs" but expose modern stuff, which would include event constructors presumably. Aligning seems easiest.
Description
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