Backbone.Mutators

Backbone plugin to override getters and setters with logic

Backbone plugin to override getters and setters with logic



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Ever wanted Backbone to have getters and setters you can override with your own logic? Yes?! Then Backbone.Mutators is the missing tool in your chain...

The plugin itself implements the Universal Module Definition (UMD). You can use it with a CommonJS like loader, or with an AMD loader or via vanilla javascript.

The plugin has two dependencies, underscore.js and backbone.js

You can directly download the Development Version or the Production Version from the root folder

$ volo add Backbone.Mutators
$ npm install Backbone.Mutators
// AMD 
require(['underscore', 'backbone', 'path/to/backbone.mutators'], function (_BackboneMutators) {
  /* Do stuff with Backbone here */
});
// CommonJS 
var _ = require('underscore');
var Backbone = require('backbone');
var Mutators = require('backbone.mutators');
<!-- Vanilla javascript -->
<script src="path/to/underscore.js"></script>
<script src="path/to/backbone.js"></script>
<script src="path/to/backbone.mutators.js"></script>
<script>
    console.log(Backbone.Mutators); // Backbone and the Mutators property are globals
</script> 

Some lines of code explain more then thousand words...

 var User = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        fullnamefunction () {
            return this.get('firstname') + ' ' + this.get('lastname');
        }
    },
    defaults: {
        firstname: 'Sugar',
        lastname: 'Daddy'
    }
 });
 
 var user = new User();
 // use get to get the 'mutated' value 
 user.get('fullname') // 'Sugar Daddy' 
 // serialize the model and see the 'mutated' value in the resulting JSON 
 user.toJSON() // '{firstname: 'Sugar', lastname: 'Daddy', fullname: 'Sugar Daddy'}' 
 var State = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        statusfunction () {
            return this.get('status') === true ? 'Workish' : 'Bad bad error';
        }
    },
    defaults: {
        status: true
    }
 });
 
 var state = new State();
 // use get to get the 'mutated' value 
 state.get('status') // 'Workish' 
 // serialize the model and see the 'mutated' value in the resulting JSON 
 state.toJSON() // '{status: 'Workish'}' 
 var User = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        fullname: {
            setfunction (keyvalueoptionsset) {
                var names = value.split(' ');
                this.set('firstname', names[0], options);
                this.set('lastname', names[1], options);
            },
            getfunction () {
                return this.get('firstname') + ' ' + this.get('lastname');
            }
        }
    },
    defaults: {
        firstname: 'Sugar',
        lastname: 'Daddy'
    }
 });
 
 var user = new User();
 // use get to get the 'mutated' value 
 user.set('fullname', 'Big Mama', {silent: true});
 // serialize the model and see the 'mutated' value in the resulting JSON 
 user.get('fullname') // 'Big Mama' 
 user.get('firstname'); // 'Big' 
 user.get('lastname'); // 'Mama' 
 var User = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        fullname: {
            setfunction (keyvalueoptionsset) {
                var names = value.split(' ');
                this.set('firstname', names[0], options);
                this.set('lastname', names[1], options);
            },
            getfunction () {
                return this.get('firstname') + ' ' + this.get('lastname');
            }
        }
    },
    defaults: {
        firstname: 'Sugar',
        lastname: 'Daddy'
    }
 });
 
 var user = new User();
 
 // bind mutator event 
 user.bind('mutators:set:fullname', function () {
    console.log('Somebody sets a full name');
 });
 
 // bind model events 
 user.bind('change:firstname', function () {
    console.log('Somebody changed the first name');
 });
 
  // bind model events 
 user.bind('change:lastname', function () {
    console.log('Somebody changed the last name');
 });
 
 // use get to get the 'mutated' value 
 user.set('fullname', 'Big Mama');
 
 // serialize the model and see the 'mutated' value in the resulting JSON 
 user.get('fullname') // 'Big Mama' 
 user.get('firstname'); // 'Big' 
 user.get('lastname'); // 'Mama' 
 var User = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        fullname: {
            setfunction (keyvalueoptionsset) {
                var names = value.split(' ');
                this.set('firstname', names[0], options);
                this.set('lastname', names[1], options);
            },
            getfunction () {
                return this.get('firstname') + ' ' + this.get('lastname');
            }
        }
    },
    defaults: {
        firstname: 'Sugar',
        lastname: 'Daddy'
    }
 });
 
 var user = new User();
 
 // bind mutator event 
 // will never be run 
 user.bind('mutators:set:fullname', function () {
    console.log('Somebody sets a full name');
 });
 
 // bind model events 
 // will still run 
 user.bind('change:firstname', function () {
    console.log('Somebody changed the first name');
 });
 
 // bind model events 
 // will still run 
 user.bind('change:lastname', function () {
    console.log('Somebody changed the last name');
 });
 
 // use get to get the 'mutated' value 
 user.set('fullname', 'Big Mama', {mutators: {silence: true}});
 
 // serialize the model and see the 'mutated' value in the resulting JSON 
 user.get('fullname') // 'Big Mama' 
 user.get('firstname'); // 'Big' 
 user.get('lastname'); // 'Mama' 
 var Spicy = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        iAcceptOnlyLowercaseStuff: {
            setfunction (keyvalueoptionsset) {
                // call the original setter with the lowercased value 
                set(key, value.toLowerCase(), options);
            }
        }
    },
    defaults: {
        iAcceptOnlyLowercaseStuff: 'sugar'
    }
 });
 
 var spicy = new Spicy();
 // use get to get the 'mutated' value 
 spicy.set('iAcceptOnlyLowercaseStuff', 'SALT');
 spicy.get('iAcceptOnlyLowercaseStuff') // 'salt' 
 var User = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        fullnamefunction (keyvalueoptionsset) {
            if(key){
                var names = value.split(' ');
                this.set('firstname', names[0], options);
                this.set('lastname', names[1], options);
            }
 
            return this.get('firstname') + ' ' + this.get('lastname');
        }
    },
    defaults: {
        firstname: 'Sugar',
        lastname: 'Daddy'
    }
 });
 var User = Backbone.Model.extend({
    // Define mutator properties 
    mutators: {
        fullname: {
            setfunction (keyvalueoptionsset) {
                var names = value.split(' ');
                this.set('firstname', names[0], options);
                this.set('lastname', names[1], options);
            }
            getfunction () {
                return this.get('firstname') + ' ' + this.get('lastname');
            }
        },
        passwordfunction () {
            return md5(this.password);
        }
    },
    defaults: {
        firstname: 'Sugar',
        lastname: 'Daddy'
    }
 });

Defining a getter as transient means that it will be omitted when Backbone saves the model. This is useful if the backend system (whatever Backbone is syncing to) fails if you send it a property that does not actually exist on the model. Note that this only works for mutators defined with a get() function.

In the example below, the fullName property will be available when toJSON is called under non-syncing circumstances--for example, when providing this model to a template--but will be omitted from the JSON when sync is called (because you called the sync() or save() method), and will not be sent to the server.

var Model = Backbone.Model.extend({
  defaults:{
    firstName:"Iain",
    middleInit:"M",
    lastName:"Banks"
  },
  mutators:{
    fullName:{
      getfunction() {
        var fullName = this.get("firstName");
        fullName += " " + this.get("middleInit");
        fullName += "" + this.get("lastName");
        return fullName;
      },
      transient: true
    }
  }
});

James Brown (@ibjhb) has written a blog article about Mutators (Exploring Backbone.Mutators)

  • Extended mutators check #38
  • Allow to specify custom isSaving() method to detect when toJSON() is cal... #36
  • Add mutator dependancies and change events #33
  • Made compatible with browserify #32
  • Backbone dependency version bump #32
  • Change get context to modal instead of attributes
  • Added single getter / setter method
  • Change get context to modal instead of attributes
  • Added single getter / setter method
  • Removed the Cake based build process and moved to grunt
  • Mutators now integrates itself to backbone, no more manual extending needed
  • Added the {mutator: {silent: true}} option to prevent mutator set events from firering
  • Added unit tests for the new features
  • Moved from jslint to jshint
  • Tweaked docs
  • Removed not needed jquery and qunit-logging submodule / npm dependencies
  • Added the original Backbone.Model.set function as a fourth paramter for the mutated set
  • Added a 'mutators:set:{{YOUR_MUTATOR_PROPERTY}}' event when setting mutated properties
  • Added unit tests for the new features
  • Extended/fixed documentation
  • Added inline version tag [NOTE: Version 0.2.0 is fully backwards compatible]
  • Initial Release