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purescript-halogen / purescript-halogen-vdom

An extensible virtual-dom library for PureScript.
Apache License 2.0
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why diffProp function gets most recent property value on "value" update? #40

Open srghma opened 4 years ago

srghma commented 4 years ago

here https://github.com/purescript-halogen/purescript-halogen-vdom/blob/8b91e55019060f50779dba20959f47cf4b60678d/src/Halogen/VDom/DOM/Prop.purs#L149-L155

well, I kind of understand why, but still want to know the explanation

the other question is should we update other propNames this way?

for example react calls value, checked, selected the Controlled attributes and handles them differently (diffHydratedProperties)

natefaubion commented 4 years ago

In many browsers, though it may not be the case anymore, setting the input value always resets the cursor position/selection. This avoids setting it if it has not changed so as not to reset the cursor when you are typing. It's a common bit of virtual DOM "lore".

https://github.com/elm/virtual-dom/blob/5a5bcf48720bc7d53461b3cd42a9f19f119c5503/src/Elm/Kernel/VirtualDom.js#L496 https://github.com/snabbdom/snabbdom/blob/ffc166cdb4beae1c800ce2132821baea1c547d6f/src/modules/props.ts#L27

srghma commented 4 years ago

snabbdom does this only for value, elm does this for value and checked

why elm does this for checked too?

natefaubion commented 4 years ago

I don't know the answer to that. I've never had issues with checked. You could maybe follow the blame for that code.

srghma commented 4 years ago

it comes from this https://github.com/elm/virtual-dom/issues/117 issue

notice the checked False in this example https://ellie-app.com/qzwpBK5xxMa1

I dont know if this happens in halogen too