Numeric field validation issues

[StephenCWills]

Numeric fields are validated by forcing numeric conversion as the user types, leading to the following issues (and possibly more).

• Erasing the value in the field results in 0 instead of a validation error.
• Entering a decimal point at the beginning or end of a number doesn't work.
• Entering two decimals points in the middle of a number results in NaN instead of a validation error.

[clackner-gpa]

Currently the value updates as the user types. We can change the behavior of input fields to update and validate Values on loosing focus only. However that would need to be changed in https://github.com/GridProtectionAlliance/gpa-gemstone/tree/master/react-forms

[StephenCWills]

I think it would be better if the user's input was kept as-is and simply raised validation errors. Imagine if the user accidentally typed the letter 'q' before Tab when they were trying to move to the next field. Would their input change to NaN, forcing them to go back and re-type the whole thing? If the validation always forcefully produces a valid result, then mistakes like that could get easily overlooked.

That said, I know that numeric field validation has implications in some tools when it comes to databinding so this may be unavoidable. If that is the case here, we should definitely change numeric fields to validate on losing focus instead.