When switching between two forms, if the structure of the HTML is similiar enough, the virtual DOM will reuse the existing input elements and change the properties/attributes around.
Attributes that do not exist in the current version don't seem to get removed, but they are assigned null value. A required property will be false, a number property will be 0. String properties get the empty string. Empty pattern strings don't validate though. So you end up with a phantom pattern on your input field that will prevent validation.
The problem shows up in current Firefox and Chrome.
A simple example that shows the problem when cut and pasted to elm-lang.org/try
https://gist.github.com/grmble/c15e9258a90e1a8bfb9417cae6d0af55
If you click "Show Demo 2" and then "Show Demo 1", the input field has a permanent red border.
When switching between two forms, if the structure of the HTML is similiar enough, the virtual DOM will reuse the existing input elements and change the properties/attributes around.
Attributes that do not exist in the current version don't seem to get removed, but they are assigned null value. A required property will be false, a number property will be 0. String properties get the empty string. Empty pattern strings don't validate though. So you end up with a phantom pattern on your input field that will prevent validation.
The problem shows up in current Firefox and Chrome.
A simple example that shows the problem when cut and pasted to elm-lang.org/try
https://gist.github.com/grmble/c15e9258a90e1a8bfb9417cae6d0af55
If you click "Show Demo 2" and then "Show Demo 1", the input field has a permanent red border.