FilterPredicate.ts

const eqString = Eq.fromEquals<string>((x, y) => x === y);

interface Animal {
  name: string;
}

interface SingleAnimalZoo {
  animal: Animal;
}

const eqZoo: Eq.Eq<SingleAnimalZoo> = F.pipe(
  eqString,
  Eq.contramap((animal: Animal): string => animal.name),
  Eq.contramap((zoo: SingleAnimalZoo) => zoo.animal)
);

const eqAnimal = Eq.fromEquals<Animal>((x, y) =>
  eqString.equals(x.name, y.name)
);

eqString.equals('a', 'b'); // false