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ember-changeset-validations: Validations for ember-changeset

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ember-changeset-validations is a companion validation library to ember-changeset. It's really simple to use and understand, and there are no CPs or observers anywhere – it's mostly just functions.

Since ember-changeset is required to use this addon, please see documentation there on how to install and use changesets.

To install if your app is on ember-source >= 3.13:

ember install ember-changeset-validations

To install if your app is on ember-source < 3.13:

ember install ember-changeset-validations@v2.2.1

Starting with v4 this addon does not install ember-changeset so make sure to list it in your devDependencies (for apps) or dependencies (for addons).

Watch a 6-part video series on ember-changeset and ember-changeset-validations presented by EmberScreencasts.


This addon updates the changeset helper by taking in a validation map as a 2nd argument (instead of a validator function). This means that you can very easily compose validations and decouple the validation from the underlying model.

{{! application/template.hbs}}
    @changeset={{changeset user EmployeeValidations}}
    @submit={{action "submit"}}
    @rollback={{action "rollback"}} />

    @changeset={{changeset user AdminValidations}}
    @submit={{action "submit"}}
    @rollback={{action "rollback"}} />

A validation map is just a POJO (Plain Old JavaScript Object). Use the bundled validators from ember-changeset-validations to compose validations or write your own. For example:

// validations/employee.js
import {
} from 'ember-changeset-validations/validators';
import validateCustom from '../validators/custom'; // local validator
import validatePasswordStrength from '../validators/password-strength'; // local validator

export default {
  firstName: [
    validateLength({ min: 4 })
  lastName: validatePresence(true),
  age: validateCustom({ foo: 'bar' }),
  email: validateFormat({ type: 'email' }),
  password: [
    validateLength({ min: 8 }),
    validatePasswordStrength({ minScore: 80 })
  passwordConfirmation: validateConfirmation({ on: 'password' })

Then, you can use the POJO as a property on your Component or Controller and use it in the template:

import Component from '@glimmer/component';
import EmployeeValidations from '../validations/employee';
import AdminValidations from '../validations/admin';

export default class EmployeeComponent extends Component {
  EmployeeValidations = EmployeeValidations;
  AdminValidations = AdminValidations;
    @changeset={{changeset user this.EmployeeValidations}}
    @submit={{action "submit"}}
    @rollback={{action "rollback"}} />

Moreover, as of 3.8.0, a validator can be an Object or Class with a validate function.

import fetch from 'fetch';

export default class PersonalNoValidator {

  async validate(key, newValue, oldValue, changes, content) {
    try {
      await fetch(
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ data: newValue })

      return true;
    } catch (_) {
      return 'Personal No is invalid';

When creating the Changeset programmatically instead of using the changeset helper, you will have to apply the lookupValidator function to convert the POJO to a validator function as expected by Changeset:

import Component from '@glimmer/component';
import EmployeeValidations from '../validations/employee';
import lookupValidator from 'ember-changeset-validations';
import Changeset from 'ember-changeset';

export default class ChangesetComponent extends Component {
  constructor() {
    this.changeset = new Changeset(this.model, lookupValidator(EmployeeValidations), EmployeeValidations);
    @submit={{action "submit"}}
    @rollback={{action "rollback"}} />

ember-changeset and ember-changeset-validations both also support creating changesets from promises. However, because that will also return a promise, to render in your template you will need to use a helper like await from ember-promise-helpers.

Validator API

ember-changeset-validations utilizes ember-validators as a core set of validators.

All validators take a custom message option.


Validates presence/absence of a value.

👉 All Options

  propertyName: validatePresence(true), // must be present
  propertyName: validatePresence(false) // must be blank
  propertyName: validatePresence({ presence: true }) // alternative option syntax
  propertyName: validatePresence({ presence: true, ignoreBlank: true }) // If ignoreBlank true, treats an empty or whitespace string as not present.

on option for presence

Only validates for presence if any of the other values are present

  password: validatePresence({ presence: true, on: 'ssn' })
  password: validatePresence({ presence: true, on: [ 'ssn', 'email', 'address' ] })
  password: validatePresence({ presence: false, on: 'alternative-login' })

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Validates the length of a String or an Array.

👉 All Options

  propertyName: validateLength({ min: 1 }), // 1 or more
  propertyName: validateLength({ max: 8 }), // up to 8
  propertyName: validateLength({ min: 1, max: 8 }), // between 1 and 8 (inclusive)
  propertyName: validateLength({ is: 16 }), // exactly 16
  propertyName: validateLength({ allowBlank: true }) // can be blank

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This API accepts valid Date objects or a Date in milliseconds since Jan 1 1970, or a functiom that returns a Date. Strings are currently not supported. It is recommended you use use native JavaScript or you library of choice to generate a date from your data.

  propertyName: validateDate({ before: new Date('3000-01-01') }), // must be before 1st Jan. 3000
  propertyName: validateDate({ onOrBefore: Date.parse(new Date('3000-01-01')) }), // must be not after 1st Jan. 3000
  propertyName: validateDate({ after: new Date('3000-01-01') }), // must be after 1st Jan. 3000
  propertyName: validateDate({ onOrAfter: new Date('3000-01-01') }), // must be not before 1st Jan. 3000
  propertyName: validateDate({ onOrAfter: () => new Date() }), // must not be in the past
  propertyName: validateDate({ onOrAfter: '3000-01-01' }), // Error

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Validates various properties of a number.

👉 All Options

  propertyName: validateNumber({ is: 16 }), // exactly 16
  propertyName: validateNumber({ allowBlank: true }), // can be blank
  propertyName: validateNumber({ integer: true }), // must be an integer
  propertyName: validateNumber({ lt: 10 }), // less than 10
  propertyName: validateNumber({ lte: 10 }), // less than or equal to 10
  propertyName: validateNumber({ gt: 5 }), // greater than 5
  propertyName: validateNumber({ gte: 10 }), // greater than or equal to 10
  propertyName: validateNumber({ positive: true }), // must be a positive number
  propertyName: validateNumber({ odd: true }), // must be an odd number
  propertyName: validateNumber({ even: true }), // must be an even number
  propertyName: validateNumber({ multipleOf: 7 }) // must be a multiple of 7

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Validates that a value is a member of some list or range.

👉 All Options

  propertyName: validateInclusion({ list: ['Foo', 'Bar'] }), // must be "Foo" or "Bar"
  propertyName: validateInclusion({ range: [18, 60] }), // must be between 18 and 60
  propertyName: validateInclusion({ allowBlank: true }), // can be blank

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Validates that a value is a not member of some list or range.

👉 All Options

  propertyName: validateExclusion({ list: ['Foo', 'Bar'] }), // cannot be "Foo" or "Bar"
  propertyName: validateExclusion({ range: [18, 60] }), // must not be between 18 and 60
  propertyName: validateExclusion({ allowBlank: true }), // can be blank

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Validates a String based on a regular expression.

👉 All Options

  propertyName: validateFormat({ allowBlank: true }), // can be blank
  propertyName: validateFormat({ type: 'email' }), // built-in email format
  propertyName: validateFormat({ type: 'phone' }), // built-in phone format
  propertyName: validateFormat({ type: 'url' }), // built-in URL format
  propertyName: validateFormat({ regex: /\w{6,30}/ }) // custom regular expression
  propertyName: validateFormat({ type: 'email', inverse: true }) // passes if the value doesn't match the given format

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Validates that a field has the same value as another.

👉 All Options

  propertyName: validateConfirmation({ on: 'password' }), // must match 'password'
  propertyName: validateConfirmation({ allowBlank: true }), // can be blank

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Writing your own validators

Adding your own validator is super simple – there are no Base classes to extend! Validators are just functions. All you need to do is to create a function with the correct signature.

Create a new validator using the blueprint:

ember generate validator <name>

ember-changeset-validations expects a higher order function that returns the validator function. The validator (or inner function) accepts a key, newValue, oldValue, changes, and content. The outer function accepts options for the validator.

Synchronous validators

For example:

// validators/custom.js
export default function validateCustom({ min, max } = {}) {
  return (key, newValue, oldValue, changes, content) => {
    // validation logic
    // return `true` if valid || error message string if invalid

Asynchronous validators

In addition to conforming to the function signature above, your validator function should return a Promise that resolves with true (if valid), or an error message string if invalid.

For example:

export default function validateUniqueness(opts) {
  return (key, newValue, oldValue, changes, content) => {
    return new Promise((resolve) => {
      // validation logic
      // resolve with `true` if valid || error message string if invalid

Using custom validators

That's it! Then, you can use your custom validator like so:

// validations/custom.js
import { validateLength } from 'ember-changeset-validations/validators';
import validateUniqueness from '../validators/unique';
import validateCustom from '../validators/custom';

export default {
  firstName: validateCustom({ min: 4, max: 8 }),
  lastName: validateCustom({ min: 1 }),
  email: [
    validateFormat({ type: 'email'}),


Since validators are higher order functions that return functions, testing is straightforward and requires no additional setup:

import validateUniqueness from 'path/to/validators/uniqueness';
import { module, test } from 'qunit';

module('Unit | Validator | uniqueness');

test('it does something', function(assert) {
  let key = 'email';
  let options = { /* ... */ };
  let validator = validateUniqueness(options);

  assert.equal(validator(key, undefined), /* ... */);
  assert.equal(validator(key, null), /* ... */);
  assert.equal(validator(key, ''), /* ... */);
  assert.equal(validator(key, ''), /* ... */);

Validation composition

Because validation maps are POJOs, composing them couldn't be simpler:

// validations/user.js
import {
} from 'ember-changeset-validations/validators';

export default {
  firstName: validatePresence(true),
  lastName: validatePresence(true)

You can easily import other validations and combine them using Object.assign.

// validations/adult.js
import UserValidations from './user';
import { validateNumber } from 'ember-changeset-validations/validators';

export const AdultValidations = {
  age: validateNumber({ gt: 18 })

export default Object.assign({}, UserValidations, AdultValidations);

Custom validation messages

Each validator that is a part of this library can utilize a message property on the options object passed to the validator. That message property can either be a string or a function.

If message is a string, you can put particular placeholders into it that will be automatically replaced. For example:

  propertyName: validatePresence({ presence: true, message: '{description} should be present' })

{description} is a hardcoded placeholder that will be replaced with a normalized version of the property name being validated. Any other placeholder will map to properties of the options object you pass to the validator.

Message can also accept a function with the signature (key, type, value, context). Key is the property name being validated. Type is the type of validation being performed (in the case of validators such as number or length, there can be a couple of different ones.) Value is the actual value being validated. Context maps to the options object you passed to the validator.

If message is a function, it must return the error message as a string.

Overriding validation messages

If you need to be able to override the entire validation message object, simply create a module at app/validations/messages.js, exporting a POJO with the following keys:

// app/validations/messages.js
export default {
  inclusion: // '{description} is not included in the list',
  exclusion: // '{description} is reserved',
  invalid: // '{description} is invalid',
  confirmation: // "{description} doesn't match {on}",
  accepted: // '{description} must be accepted',
  empty: // "{description} can't be empty",
  blank: // '{description} must be blank',
  present: // "{description} can't be blank",
  collection: // '{description} must be a collection',
  singular: // "{description} can't be a collection",
  tooLong: // '{description} is too long (maximum is {max} characters)',
  tooShort: // '{description} is too short (minimum is {min} characters)',
  between: // '{description} must be between {min} and {max} characters',
  before: // '{description} must be before {before}',
  onOrBefore: // '{description} must be on or before {onOrBefore}',
  after: // '{description} must be after {after}',
  onOrAfter: // '{description} must be on or after {onOrAfter}',
  wrongDateFormat: // '{description} must be in the format of {format}',
  wrongLength: // '{description} is the wrong length (should be {is} characters)',
  notANumber: // '{description} must be a number',
  notAnInteger: // '{description} must be an integer',
  greaterThan: // '{description} must be greater than {gt}',
  greaterThanOrEqualTo: // '{description} must be greater than or equal to {gte}',
  equalTo: // '{description} must be equal to {is}',
  lessThan: // '{description} must be less than {lt}',
  lessThanOrEqualTo: // '{description} must be less than or equal to {lte}',
  otherThan: // '{description} must be other than {value}',
  odd: // '{description} must be odd',
  even: // '{description} must be even',
  positive: // '{description} must be positive',
  multipleOf: // '{description} must be a multiple of {multipleOf}',
  date: // '{description} must be a valid date',
  email: // '{description} must be a valid email address',
  phone: // '{description} must be a valid phone number',
  url: // '{description} must be a valid url'

In the message body, any text wrapped in single braces will be replaced with their appropriate values that were passed in as options to the validator. For example:

import buildMessage from 'ember-changeset-validations/utils/validation-errors';
// validators/custom.js
export default function validateIsOne(options) {
  return (key, newValue, oldValue, changes, content) => {
    return newValue === 1 || buildMessage(key, { type: 'isOne', value: newValue, context: options });
// validations/foo.js
export default {
  mySpecialNumber: validateIsOne({ foo: 'foo' }})

The above will look for a key isOne in your custom validation map, and use keys defined on the options object (in this case, foo) to replace tokens. With the custom validator above, we can add:

// app/validations/messages.js
export default {
  isOne: '{description} must equal one, and also {foo}'

Will render: My special number must equal one, and also foo.

Raw error output

By default, ember-changeset-validations returns the errors as plain strings. In some situations, it may be preferable for the developer that the library returns a description of the errors; internationalisation (i18n) for example, or finer-grained error output.

To have ember-changeset-validations return such data structure, add the following to you config/environment.js

let ENV = {
  'changeset-validations': { rawOutput: true }

This will return an object with the following structure, that you can then pass to your applications's error processing:

  value, // the value to validate
  type, // the type of the error (`present`, `blank`...)
  message, // the **unprocessed** error message
  context: {
    description // the description of the field
    // ...and other options given to configure the validator


We're grateful to these wonderful contributors who've contributed to ember-changeset-validations:


  • git clone <repository-url> this repository
  • cd ember-changeset-validations
  • npm install


Running Tests

  • npm test (Runs ember try:each to test your addon against multiple Ember versions)
  • ember test
  • ember test --server


  • ember build

For more information on using ember-cli, visit