Element: Expose dirty and invalid states on el-form

[psi-4ward]

I would like to show the save button only when model has some changes and everything is valid.

Probably we could $emit('state', formState)

[element-bot]

Hello, this issue has been closed because it does not conform to our issue requirements. Please submit issues with issue-generator. More info can be found in #3693.

[Leopoldthecoder]

Something we'll consider in the next major version.

[williangd]

Is there any prevision for this functionality? It's a good way to disabled/enable buttons..
I was using another angular library that had this functionality and I'm really missing it.