Set value property before selectionEnd and selectionStart #157
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Changing the `value` property of a `textarea` also implicitly changes its `selectionEnd` and `selectionStart` properties. Since virtual-dom isn't aware of this, the in-memory copy of the dom now differs from the real dom in these properties, leading to bugs. Adding the logic to handle this properly requires handling a lot of edge cases, so I couldn't find a nice way to implement it considering that these properties are uncommon and code size is important, hence this hotfix. This hotfix always considers the `selectionStart` and `selectionEnd` properties modified, like we already do with `value` and `checked`. Setting these properties to themselves (moving the cursor/selection to where it already is) is idempotent so this should be safe.
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Is there an Ellie or other example we can try this out on? |
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Its not clear what issue this PR actually solves. Is there an issue this can be linked to, or can you provide a little more explanation here? |
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Changing the
valueproperty of atextareaalso implicitly changes (step 4) itsselectionEndandselectionStartproperties. Since virtual-dom isn't aware of this, the in-memory copy of the dom now differs from the real dom in these properties, leading to bugs.Adding the logic to handle this properly requires handling a lot of edge cases, so I couldn't find a nice way to implement it considering that these properties are uncommon and code size is important, hence this hotfix.
This hotfix always considers the
selectionStartandselectionEndproperties modified, like we already do withvalueandchecked. Setting these properties to themselves (moving the cursor/selection to where it already is) is idempotent so this should be safe.I've tested this patch by modifying the js output by the compiler.
I've looked through the html spec; there doesn't seem to be other properties being implicitly modified.