su-define-object

Build trees of ES5 property objects with hasOne/hasMany relationships.

Properties can have basic types: string|number|boolean etc.

Properties can have custom setters.

Objects extend EventEmitter.

Dependencies

node v0.11.12

Tests

npm install -d npm test

Usage

create an nested object constructor

var define = require('su-define-object');


var Tree = define('Tree', {

  properties: [
    {
      species: {
        enumerable: true,
        type: 'string'
      }
    }
  ],

  hasOne: {
    trunk: Trunk,
    rootSystem: RootSystem
  },

  hasMany: {
    branches: Branch
  }

});


var Trunk = define('Trunk', {
  properties: [
    {
      diameter: {
        enumerable: true,
        type: 'number'
      }
    }
  ]
});


var RootSystem = define('RootSystem', {
  properties: [
    {
      systemType: {
        enumerable: true,
        type: 'string'
      }
    }
  ]
});


var Branch = define('Branch', {
  properties: [
    {
      leaves: {
        enumerable: true,
        type: 'number'
      }
    }
  ]
});

instantiate a nested instance

var oak = new Tree({
  species: "Oak",
  trunk: {
    diameter: 10
  },
  rootSystem: {
    systemType: "Tap root"
  },
  branches: [
    {leaves: 10},
    {leaves: 20},
    {leaves: 30},
    {leaves: 40},
    {leaves: 50}
  ]
});


oak.branches[2].leaves // => 30
oak instanceof Oak // => true

instantiate an instance with no relations

var birch = new Tree({
  species: "Silver birch",
  trunk: {
    diameter: 5
  }
});

birch.trunk.diameter // => 5
birch.branches[2].leaves // => undefined

setting a property of an existing instance to an incorrect type will throw

try {

  birch.trunk.diameter = "ten";
}
catch (e) {

  e instanceof TypeError // => true
}

instantiating an instance with incorrect types will throw an array of all the errors that occured during instantiation

try {

  var elm = new Tree({
    species: 10,
    trunk: {
      diameter: "Elm"
    }
  })

}
catch (e) {

  e.length // => 2

  e[0] instanceof TypeError // => true
  e[1] instanceof TypeError // => true
}

custom setters (ES5) can be passed in the property descriptor

var Cactus = define('Cactus', {
  properties: [
    {
      spikes: {
        enumerable: true,
        set: function (val) {
          if (val === 'rainy') {
            return 100;
          }
          return 10;
        }
      }
    }
  ]
})

var cactus = new Cactus();

cactus.spikes = "dry";
cactus.spikes // => 10;

cactus.spikes = "rainy";
cactus.spikes // => 100;