✨ Support use of onInitialValueChanged prop with fields having nested properties

[allyshiasewdat]

#446 introduced the onInitialValueChanged prop to <FormState />, allowing control over the form's reset behaviour when the value of the initialValues prop changed.

The problem

When onInitialValueChanged is set to reset-where-changed, only fields whose initial values had been changed are reset. However, !== was being used to check for changes rather than a deep equality check. This meant that for fields that had nested properties, if the field's initial value pointed to a new object but with unchanged values from the previous, <FormState /> would interpret that the field's initial value had changed, and would reset it.

The suggested fix

This PR introduces a deep equality check to support having complex fields for which we cannot rely on shallow equality. It also makes the reconciliation more consistent with the deep equality check performed by default when no value is specified for onInitialValueChanged.

Some concerns

• Is there a legitimate use case for wanting to clear a field when an initial value is reassigned, even if the actual values don't change?
• Would support for the intended use case here be better achieved through using a custom function for onInitialValueChanged?

[marutypes]

👍

[michenly]

LGTM!