default_if option

V2 has a much more flexible default_if option, but you can maintain backwards compatibility with V1 using the LegacyOptions extension.

The old default_if values will continue to work (until a future Blueprinter removes the constants).

field :name, default: "N/A", default_if: Blueprinter::EMPTY_STRING

V2 style

The native V2 option allows for Procs or symbols (method names). The logic is up to you.

They’re passed a Blueprinter::V2::Context::Field object and the extracted value.

field :name, default: "N/A", default_if: ->(ctx, val) { val.empty? }
field :name, default: "N/A", default_if: :empty_string?

def empty_string?(ctx, val) = val.empty?