changeset es6 proxy

controllers.application.js

import Ember from 'ember';
import Changeset from '../lib/changeset';
import validatePresence from '../validators/presence';

let model = { foo: 'bar' };
let validations = {
	foo: validatePresence()
};
let changeset = new Changeset(model, { validations });

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  init() {
    this._super(...arguments);
  	console.log('Model', model);
  	console.log('Changeset', changeset);
    
    changeset.foo = '';
    
    console.log('changeset.foo value is:', changeset.foo);
    
	  changeset.foo = 123;
    
    console.log('changeset.foo value is:', changeset.foo);
  }
});

lib.changeset.js

import Ember from 'ember';
import validatorLookup from './validator-lookup';

const { warn } = Ember;

function createChangeset(obj, { validations }) {
  return new Proxy(obj, {
    set(target, property, value, receiver) {
      let validationResult = validatorLookup(validations, property)(property, value);
      if (validationResult.isValid) {
      	target[property] = value;
      } else {
      	warn(validationResult.message);
      }
      return true;
    }
  });
}

export default class Changeset {
	constructor() {
  	return createChangeset(...arguments);
  }
}

lib.validation-result.js

export default class ValidationResult {
	constructor(validation, message) {
  	this.validation = validation;
    this.message = message;
  }
  
  get isValid() {
  	return this.validation === true;
  }
  
  get isInvalid() {
  	return !this.isValid;
  }
}

lib.validator-lookup.js

export default function validatorLookup(validations, key) {
  return typeof validations[key] === 'function' && validations[key];
}

templates.application.hbs

Open console

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}

validators.presence.js

import ValidationResult from '../lib/validation-result';

export default function validatePresence() {
  return ((key, value) => {
  	return new ValidationResult(!!value, `${key} must be present`);
  });
};