const validate = require('validate.js');
const different = require('vtypes-different');
 
// you can then proceed to register the required validators.
validate.validators.different = different;

validate({}, {attr: {different: true}});
// => undefined
 
validate({attr: 'foo'}, {attr: {different: true}});
// => {attr: ["Attr must be of type differentean"]}
 
validate({attr: true, {attr: {different: true}});
// => undefined
 
validate({attr: false, {attr: {different: true}});
// => undefined
 
var constraints = {
  password: {
    different: "prevPassword"
  }
};
 
validate({password: "foo", prevPassword: "bar"}, constraints);
// => undefined
 
validate({password: "foo", prevPassword: "foo"}, constraints);
// => {password: ["Password is not different from prev password"]}