Ember.Validatable

Introduction

Ember Validatable is a simple and lightweight validation library for Ember.

Validations

Validations are added to a model by defining properties ending in either Validator or Validators.

App.User = Ember.Model.extend(Ember.Validatable, {
  firstName: attr(),
  password:  attr(),
  firstNameValidator: App.PresenceValidator,
  passwordValidators: [App.PresenceValidator, App.PasswordValidator]
});

Mixing in Ember.Validatable also adds several properties to your model:

• isValid - true if all the validations on this model are successful.
• isInvalid - the opposite of isValid.
• errors - an Enumerable containing the contents of each validation's error property (should any be invalid).

Writing Validators

Your validators should be a subclass of the Ember.Validator class. As a minimum your validator should contain an isValid computed property (dependent on the content property) which implements your logic for defining the validity of the content.

Other properties available are:

• content - the value of retrieving targetKey from target (ie the value to test for validity).
• target - the model instance for which we are validating.
• targetKey - the name of the property on target which we are validating.
• message - "is invalid." by default.
• error - by default this concatenates targetKey and message. The result of this will be placed in your models errors array property.

Validating multiple properties

Sometimes you might want to validate a selection of properties together. You might be tempted to reach into target and get the properties you need, but this would be unwise, as these additional properties will not have the validator's observer configured against them, instead it's best to create a computed property and validate that:

var TimeTravelValidator = Ember.Validator.extend({
  error: null,
  isValid: function() {
    var speed = this.get('target.speed');
    var power = this.get('target.powerLevel');
    if (speed < 88) {
      this.set('error', 'Must be travelling at least 88mph to engage the flux capacitor');
      return false;
    }
    if (power < 1210000000) { // 1.21GW
      this.set('error', 'We need at least 1.21 giga-watts of available power to engage the flux capacitor');
      return false;
    }
    return true;
  }.property('content')
});

App.Delorean = Ember.Object.extend(Ember.Validatable, {
  speed: '17mph',
  powerLevel: '99000000',

  fluxCapacitorRequirements: function() {
    // Technically, we can return anything here, as long as it
    // triggers.
    return [ this.get('speed'), this.get('powerLevel') ];
  }.property('speed', 'powerLevel'),

  fluxCapacitorRequirementsValidator: TimeTravelValidator
});