Checkit.js

A DOM-independent validation library for Node.js, io.js and the browser.

It supports both sync

It allows you to seamlessly validate full javascript objects, defining custom messages, labels, and validations, with full support for asynchronous validations with promises. It supports conditional validations, and has powerful, consistent error structuring and utility methods for manipulating your errors' output any way you can imagine.

var mainRules = Checkit(rules);

mainRules
  .run(obj, context)
  .then(function(validatedFields) {
    console.log('The fields: ' + _.keys(validatedFields).join(', ') + ' were validated!');
  })
  .caught(Checkit.Error, function(err) {
    $("#errors").html(err.map(function(val, key) {
      return '<li>' + key + ': ' + val.first().message + '</li>';
    }).join(''));
  });

Node.js

npm install checkit

Browser

The easiest way to use the library is with webpack or browserify

API:

Checkit(validators, [options])

The main Checkit constructor may be called with or without the new keyword, taking a hash of fields/rules for these fields to be validated.

Options:

language

Used to specify the default language key for using a particular language file, currently en, es, ru and fr are supported.

labels

Specifies labels for use in error messages for specific keys

messages

Adds specific messages for individual errors

Example:

checkit.run

checkit.validate (alias)

var checkit = new Checkit({
  firstName: 'required',
  lastName: 'required',
  email: ['required', 'email']
});

var body = {
  email: 'test@example.com',
  firstName: 'Tim',
  lastName: 'Griesser',
  githubUsername: 'tgriesser'
};

checkit.run(body).then(function(validated) {
  console.log(validated);
}).catch(Checkit.Error, function(err) {
  console.log(err.toJSON());
})

checkit.runSync

checkit.validateSync (alias)

var checkit = new Checkit({
  firstName: 'required',
  lastName: 'required',
  email: ['required', 'email']
});

var body = {
  email: 'test@example.com',
  firstName: 'Tim',
  lastName: 'Griesser',
  githubUsername: 'tgriesser'
};

var [err, validated] = checkit.validateSync(body)

// ...

Checkit.check(key, value, rules)

Checkit.check('email', email, ['required', 'email'])
  .catch(function(err) {
    console.log(err.message)
  });

Checkit.checkSync(key, value, rules)

// ES6...
var [err, resp] = Checkit.checkSync('email', email, ['required', 'email'])  

if (err) {

} else {
  // ...
}

Available Validators

Conditional Validations

Sometimes you may wish to require a given field conditionally, for example require a field only if another field has a greater value than 100. Or you may need two fields to have a given value only when another field is present. Adding these validation rules doesn't have to be a pain. First, create a Checkit instance with the main rules that never change:

var checkit = new Checkit({
  firstName: ['required'],
  lastName: ['required'],
  email: ['required', 'email']
});

Then use the maybe method to add additional rules:

.maybe(rules, handler)

The first of the maybe method is the hash of validation fields / settings, similar to the main Checkit object. The second argument is a function, evaluated with the object being validated as the first argument and the context passed to run (if any) as a second argument. If it returns explicitly true or with a promise fulfilling with true, it will add an additional validator to the Checkit object.

This method makes building complex conditional validations a snap.

// In this example, the "authorBio" field is only required if there are
// more than 5 books specified in the input object
checkit.maybe({authorBio: ['required', 'max:500']}, function(input) {
  return input.books > 5;
});

// In this example, the "authorBio" field is only required if specified by the context
checkit.maybe({authorBio: ['required', 'max:500']}, function(input, context) {
  return context.requireBio;
});

checkit.run(someObj, { requireBio: true })

Advanced & Custom Validators:

First, and simplest, you can specify a function on the validation array for a property. For example:

{
  email: ['email', function(val) {
    return knex('accounts').where('email', '=', val).then(function(resp) {
      if (resp.length > 0) throw new Error('The email address is already in use.')
    })
  }]
}

You may also specify an object in one of the validator slots, specifying at the minimum a rule, and optionally params, label, and message.

{
  email: {
    scenarios: 'create',  
    rule: 'email',
    label: 'Email'
  },
  first_name: [{
    scenarios: ['create', 'delete'],  
    rule: 'required',
    message: 'You must supply a first name value!!',
    when: 1 + 1 > 2
  }, {
    rule: 'minLength:3',
    label: 'first name of this application'
  }],
  arr: {
    rule: 'contains',
    params: [10] // Number => Different behavior than "contains:10"
  }
}

You may also use the context parameter passed to run when using a function on the validation array of a property. This can be particularly useful if your validation function needs to execute within a transaction:

{
  email: {
    rule: function(val, params, context){
      var query = knex('users');
      if (context && context.transacting){
        query.transacting(context.transacting);
      }

      return query.where('email', '=', val)
        .andWhere('id', '<>', this.target.id)
        .then(function(resp){
          if (resp.length > 0){
            throw new Error('The email address is already in use.');
          }
        });
    }
  }
}

Second, you may add a custom validator to the Checkit.Validator object's prototype, returning a boolean value or a promise.

Checkit.Validator.prototype.unused = function(val, table, column) {
  return knex(table).where(column, '=', val).andWhere('id', '<>', this._target.id).then(function(resp) {
    if (resp.length > 0) {
      throw new Error('The ' + table + '.' + column + ' field is already in use.');
    }
  });
}

{
  email: ['email', 'unused:accounts:email']
}

Checkit Errors

One of the main features of Checkit is the error handling; By extending the error object with utility methods from underscore, the errors are even easier to work with.

• Checkit.Error
• Checkit.FieldError
• Checkit.ValidationError

Checkit.Error

The main Error object, Checkit.Error is returned from the has several helper methods & properties, as well as a number of utility methods:

.errors

The "errors" property of a Checkit.Error object is a hash of errors for each of the fields which are considered "invalid" in any way by the validation rules. The keys in this hash are the invalid fields, and the values are Checkit.FieldError objects, which in-turn have an errors attribute, an array containing errors for each failed rule.

.get(key)

The get method returns the Checkit.FieldError object for a specific key, or undefined if one does not exist.

.toString([flat])

Useful for debugging, the toString method converts the Checkit error into a human readable representation of the failed validation. If the flat argument is passed as a "truthy" value, it will output only the first ValidationError in the FieldError; otherwise it will output each validation message in a comma separated string.

.toJSON()

Converts the current error object to a json representation of the error, for easy use/refinement elsewhere. For other methods, such as map, reduce, each, see the utility methods section.

Checkit.FieldError

A FieldError is an error that contains all of the sub-errors for the validation of an individual item in the validated hash.

fieldError.errors

The errors property of a FieldError is

Checkit.ValidationErrror

A ValidationError is the result of an individual error in the field rule.

Error Utility Methods

The following methods are underscore methods proxied to the Checkit.Error and Checkit.FieldError objects, for easy manipulation of the .errors object contained in each.

shared (Checkit.Error & FieldError)

• each
• forEach
• map
• reduce
• reduceRight
• find
• filter
• reject
• invoke
• toArray
• size
• shuffle

Checkit.Error only

• keys
• values
• pairs
• invert
• pick
• omit

Checkit.FieldError only

• first
• initial
• rest
• last

Other Helpers

Checkit.labelTransform(fn)

The Checkit.labelTransform method takes a function that receives the field name and returns a human-readable label for use in error messages.

Change Log

0.7.0

• Expect a global Promise instance. Breaking change #69
• Add meaningful message for integer validation. #46
• Add string validation. #58
• Compatible with Lodash 4.x only. #55
• More permissive email regex. #61, #68
• Only bundle required lodash methods. #69

0.6.0

• Separate codepath for server (bluebird) and client (when.js)
• Add French and Russian translations.
• Allow new longer top level domains in emails.

0.5.1

• Minor bugfixes

0.5.0

• Major internal refactoring, using when.js to shave bytes in the browser build.
• Added sync api with runSync / checkSync / validateSync
• Alias validate for run

0.2.0

• CheckIt is now renamed Checkit
• Flipped the validations and target arguments, so the syntax is now Checkit(validations).run(input) rather than Checkit(input).run(validations), allowing for re-use of the validation objects.
• Tons of other internal changes, probably too many to list, pretty much a rewrite from 0.1.0

0.1.0

Initial release