Handling `undefined` as a missing value in Schema Struct

In a

Schema.Struct({ foo: Schema.Boolean })

Schema.Struct({ foo: Schema.Boolean })

, is there a way to treat

undefined

undefined

as a missing value?
Right now

decode({ foo: undefined })

decode({ foo: undefined })

returns a ParseError:

Expected Boolean, actual undefined

Expected Boolean, actual undefined

I would just like to have a

is missing

is missing

error in this case.

Is that doable? Maybe with

propertySignature

propertySignature