Email

The email field is a required field of type String, which must match a valid email format and must also be unique in the user collection.

mern-skeleton/server/models/user.model.js:

email: {
  type: String,
  trim: true,
  unique: 'Email already exists',
  match: [/.+\@.+\..+/, 'Please fill a valid email address'],
  required: 'Email is required'
},