How to validate password with Vuelidate in Vuejs

just add a custom function with the rules you want to the Vuelidate validations.

validations: {
  password: {
    required,
    // minLength: minLength(8)  // I assume you'd want something like this too
    valid: function(value) {
      const containsUppercase = /[A-Z]/.test(value)
      const containsLowercase = /[a-z]/.test(value)
      const containsNumber = /[0-9]/.test(value)
      const containsSpecial = /[#?!@$%^&*-]/.test(value)
      return !containsUppercase || !containsLowercase || !containsNumber || !containsSpecial
    }
  }
}

It'd probably be helpful to break each requirement up into a separate function, so you can set a different error message for each (which would be helpful to guide the user as to what to they need to fix).

validations: {
  password: {
    required,
    // minLength: minLength(8)  // I assume you'd want something like this too
    containsUppercase: function(value) {
      return !/[A-Z]/.test(value)
    },
    containsLowercase: function(value) {
      return !/[a-z]/.test(value)
    },
    containsNumber: function(value) {
      return !/[0-9]/.test(value)
    },
    containsSpecial: function(value) {
      return !/[#?!@$%^&*-]/.test(value)
    }
  }
}