Type Error when Defining Default for Literal Union of Strings

//Object literal may only specify known properties, and 'default' does not exist in type '{ readonly as: "Option"; }'.ts(2769
const test = Schema.optional(Schema.literal("foo", "bar"), {default: () => "foo"})

//Object literal may only specify known properties, and 'default' does not exist in type '{ readonly as: "Option"; }'.ts(2769
const test = Schema.optional(Schema.literal("foo", "bar"), {default: () => "foo"})