revalidate

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Changelog

v0.3.0

New Common Validators

isRequiredIf

isRequiredIf allows you to conditionally require a value based on the result of a predicate function. As long as your predicate function returns a truthy value, the field value will be required.

This is perfect if you want to require a field if another field value is present:

import { isRequiredIf } from 'revalidate';

const validator = combineValidators({
  username: isRequiredIf(
    values => values && !values.useEmailAsUsername
  )('Username'),
});

validator(); // { username: 'Username is required' }

validator({
  useEmailAsUsername: false,
}); // { username: 'Username is required' }

validator({
  username: 'jfairbank',
  useEmailAsUsername: false,
}); // {}

validator({
  useEmailAsUsername: true,
}); // {}, so valid

matchesPattern

matchesPattern is a general purpose validator for validating values against arbitrary regex patterns.

import { matchesPattern } from 'revalidate';

const isAlphabetic = matchesPattern(/^[A-Za-z]+$/)('Username');

isAlphabetic('abc'); // undefined, so valid
isAlphabetic('123'); // 'Username must match pattern /^[A-Za-z]+$/'

Note: matchesPattern does not require a value, so falsy values will pass.

isAlphabetic();      // undefined because not required, so valid
isAlphabetic(null);  // undefined because not required, so valid
isAlphabetic('');    // undefined because not required, so valid

---

Return multiple errors as an object

In addition to returning multiple errors as an array with composeValidators, you can also return multiple errors as an object now. This is useful if you want to name your errors and react accordingly based on the type of error. Instead of passing in validators as a variadic number of arguments, pass in all validators inside an object. The keys of your object will the keys used in the error object. Don't forget to still supply the multiple: true option!

import { createValidator, composeValidators } from 'revalidate';

const startsWithA = createValidator(
  message => value => {
    if (value && !/^A/.test(value)) {
      return message;
    }
  },
  field => `${field} must start with A`
);

const endsWithC = createValidator(
  message => value => {
    if (value && !/C$/.test(value)) {
      return message;
    }
  },
  field => `${field} must end with C`
);

const validator = composeValidators({
  A: startsWithA,
  C: endsWithC
})({ field: 'My Field', multiple: true });

validator('BBB');
// {
//   A: 'My Field must start with A',
//   C: 'My Field must end with C'
// }