exempel

Lean Backbone like Model and Collection for browserify.

Benefits:

• easy integration into you View, Router stack
• easy integration to your persistence flow (just listen to "change")
• small code base (at least when you let uglifify clean up lodash)

Installation

Install with npm(1):

$ npm install --save exempel

Preview

The basic idea is to have an extendable prototype which carries state you can share between different views. The reason why I did not use any existing library for this is that other libraries have a complete different model approach (e.g. scheme based) or are just too heavy.

Model

The Model prototype represents a single entity.

var util    = require('util');
var exempel = require('exempel');

function Product(source) {
  exempel.Model.call(this, source);

  this.isInternal = 'property';
  this.attributes.isA = 'real model property';

  listenToChangeEvent(this);
}

util.inherits(Product, exempel.Model);

Product.prototype.addComment = function(comment) {
  this.get('comments').push(comment);

  return this;
};

// will cache this model on change
// into the browsers session storage
function listenToChangeEvent(model) {
  model.on('change', function(key, value) {
    var source = JSON.stringify(model);

    sessionStorage.setItem('product', source);
  });
}

new Model([source])

Sets up a new Model instance with source as attributes. Will also generate a unique id on model.id. The Model itself inherits from events.EventEmitter.

Event: "change"

Emitted when you change a model attribute with set(). However as Object.observe is still experimental there is currently no way to observe properties without using a setter.

Event: "change:"

Each time you set a property next to the "change" event there will be another event "change:" where "" will be the property name. This is useful if you want to listen to the change of a specific property.

Event: "remove"

Emitted when you call model.remove(). This is actually for use with a collection so we know when to remove a model from array.

model.has(key)

Returns true if model has property key.

model.get(key)

Returns value behind property key.

model.set(source)

Merges source onto model.attributes. Also supports nested properties which can be useful on parsing form data:

form.addEventListener('submit', function(e) {
  e.preventDefault();

  // loop through each input field
  [].forEach.call(form.children, function(input) {
    // transforms "address-street" to object
    // compatible "address.street" notation
    var key = input.name.split('-').join('.');

    model.set(key, input.value);
  });
});

model.set(key, value)

Sets value on model.attributes[key].

model.remove()

Will emit an "remove" event for listening collections.

model.toJSON()

Returns deep clone of model.attributes.

Collection

The Collection prototype represents a collection of entities.

var util    = require('util');
var ldoash  = require('lodash');
var exempel = require('exempel');

function Products(source) {
  // if you do not specify Model it will use
  // the default Model
  this.Model = Product;

  exempel.Collection.call(this, source);
}

util.inherits(Products, exempel.Collection);

Products.prototype.find = function(query) {
  return lodash.find(this.models, {
    attributes: query
  });
};

new Collection([source])

Creates a new instance of Collection with pushing all items in source to collection.models. Also inherits from events.EventEmitter.

Event: "push"

Emitted when a model is added to collection. Will also be emitted by new Collection() when mapping source.

collection.on('push', function(model) {
  // add model to list element
}};
collection.push(model);

Event: "remove"

Emitted when a model is removed from collection.

collection.on('remove', function(model) {
  // remove model from list element
  // note that it is wiser to just let the view
  // instance listen on the models "remove" event
  // then you do not have to query the right li from list view
}};
collection.remove(model);

Event: "change"

Emitted on when collection changes by "push" or "remove". Can be used if you want to do a PUT on change. For example:

collection.on('change', function() {
  superagent.put('/comments/blabla')
    .send(collection)
    .end();
});

Also "change" will be emitted when a model in the collection changes.

collection.length

Shortcut to collection.models.length.

collection.at(index)

Returns model beeing at index of collection.models.

collection.has(uniqueid)

Returns true if model with uniqueid is inside collection.models.

collection.get(uniqueid)

Returns model with uniqueid from collection.models.

collection.push(model)

Adds model to collection. Note that model should be an instance of EventEmitter else you will get an error as the collection binds to the models "remove" event.

collection.remove(model)

Removes the model from collection.

collection.forEach(callback)

Shortcut for collection.models.forEach.

collection.toJSON()

Returns clone of collection.models with toJSON called on each model.

License

Copyright © 2014 Bodo Kaiser i@bodokaiser.io

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.