Validator.js

A simple validation module, for use server- or client-side. It depends on ES5 functionality, so in old browsers you might need something like ES5 Shim

Simple Usage

You can use Validator to quickly check a string (or in most cases an array) like so:

var myString = 'some string here';
console.log(Validator.matchesRegex(myString, /here/)); // true

Complex Construction

Alternatively you can construct a more complex set of rules, like so:

var myString = 'some string here',
    validator1 = new Validator(),
    validator2 = new Validator();
validator1.add('matchesRegex', /here/);
validator1.add('minLength', 5);
validator2.add('matchesRegex', /here/);
validator2.add('minLength', 100);
console.log(validator1.validate(myString)); // true
console.log(validator2.validate(myString)); // false, string matches regex, but isn't long enough

Error Messages

Validator.js provides error messages as an array when using the complex construction method.

var myString = 'some string here',
    validator = new Validator();
validator.add('matchesRegex', /there/);
validator.validate(myString); // returns false, because the string doesn't match
console.log(validator.errors); // contains an array of default error messages.

Custom Error Messages

You can specify a custom error message per validation by chainging a call to message() after add():

var myString = 'some string here',
    validator = new Validator();
validator.add('matchesRegex', /there/).message('You should be over there!');
validator.validate(myString); // returns false, because the string doesn't match
console.log(validator.errors); // returns ['You should be over there!']

Setting default error messages, and translating

You can add and override Validator's default error messages, and add new languages and set the default language simply by setting some properties on the Validator object. Validator will use messages specified in "lang" if available, and fallback to "defaultLang" (which is "en" unless overridden) if needed.

Validator.lang = 'XY'; // set "XY" as the current language
Validator.messages.XY = {
  unique: 'XXXYYY',
  maxLength: 'XXXXXXXX'
}
var validator = new Validator();
validator.add('unique');
validator.add('minLength', 5);
validator.add('maxLength', 10);
validator.validate([1, 2, 3]);
console.log( validator.errors ); // returns ['XXXYYY', 'The list is not long enough'];

Chaining

You can chain calls to add() and message(). The argument supplied to message() will only apply to the validation in the single preceding call to add().

var myString = 'some string here',
    validator = new Validator();
validator
    .add('matchesRegex', /there/).message('You should be over there!')
    .add('matchesRegex', /some/).message('Some is better than none')
    .add('minLength', 100).message('Not long enough');
validator.validate(myString); // returns false, because the string doesn't match
console.log(validator.errors); // returns ['You should be over there!', 'Not long enough']

Supported Validations

You can use any of these in either the simple or complex forms.

Validator.unique(Array)

Checks whether an array contains only unique elements

Validator.minLength(strOrArray, len)

Checks whether a string (or an array) is of at least a given length (inclusive)

Validator.maxLength(strOrArray, len)

Checks whether a string (or an array) is of at most a given length (inclusive)

Validator.lengthInRange(strOrArray, minLen, maxLen)

Checks whether a string (or an array) is within a given length (inclusive)

Validator.matchesRegex(strOrArray, regex)

Checks whether a string (or array of strings) matches a regular expression

Validator.isEmail(strOrArray)

Loose (i.e. overly permissive, rather than overly strict) check on whether a string (or array of strings) is a valid email address

Validator.htmlHasContent(html)

Checks whether an HTML snippet actually has any textual content, once tags are stripped and whitespace is trimmed

Validator.hasProperty(object)

Proxies to Object.hasOwnProperty

pete-otaqui / Validator.js