Express validator iteration to body check every item in the array has the correct input

Good night. I have to validate if every element in the array has a username. I'am currently using express-validator successfuly to validate only one user, but I dont know how to deal with the array.

I want to do somethink like

  req.checkBody('username', 'username is required').isEmail();

But for each element in the array. In which case the following input sends an error for the first argument in the array given that it has no username. I was thinking something like

  req.checkBody('req.body[1].username', 'username is required').isEmail();

whould work but it dosn't.

[{
  "password": "123",
  "nombre":"kila",

},
{
  "username": "vanilla@skalia.com",
  "password": "123",
}]