features.js

features.js organizes sets of actions or object methods into features, applies them, manages merging of features via inter-feature dependencies and external criteria.

• features.js
  • Basics
    • Organizational structure
    • Lifecycle
    • How features are loaded
  • The main entities:
    • FeatureSet()
      • <feature-set>.features
      • <feature-set>.setup(..)
      • <feature-set>.remove(..)
      • <feature-set>.gvGraph(..)
    • Feature(..)
    • Meta-features

Basics

var features = require('ig-features')

Organizational structure

• FeatureSet
  Contains features, defines the main feature manipulation API, acts as the target object constructor/factory.
• Feature
  Creates a feature in the feature-set, defines the feature metadata, references the feature mixin / action set and configuration.
• ActionSet / mixin
  Contains the actions/methods of the feature mixin.

// feature-set...
var App = new features.FeatureSet()

// features...
App.Feature('A', {
    // ...
})
App.Feature('B', {
    // ...
})

// meta-features...
App.Feature('all', [
    'B',
    'C',
])

// init and start the app...
var app = App.start(['all'])

Lifecycle

How features are loaded

The main entities:

FeatureSet()

FeatureSet()
    -> <feature-set>

var feature_set = new features.FeatureSet()


// define features...
// ...


// setup features...
feature_set
    .setup([
        'feature-tag',
        //...
    ])

XXX

<feature-set>.features

<feature-set>.setup(..)

<feature-set>.remove(..)

<feature-set>.gvGraph(..)

Get a Graphvis graph spec for the feature dependency graph.

Feature(..)

Standalone feature

Feature({ tag: <tag>, .. })
Feature(<tag>, { .. })
Feature(<tag>, [<suggested-tag>, .. ])
Feature(<tag>, <actions>)
	-> <feature>

Feature-set features

<feature-set>.Feature({ tag: <tag>, .. })
<feature-set>.Feature(<tag>, { .. })
<feature-set>.Feature(<tag>, [<suggested-tag>, .. ])
<feature-set>.Feature(<tag>, <actions>)
	-> <feature>
    
Feature(<feature-set>, { tag: <tag>, .. })
Feature(<feature-set>, <tag>, <actions>)
	-> <feature>

Examples:

feature_set.Feature('minimal_feature_example', {})

feature_set.Feature({
    // feature unique identifier (required)...
    tag: 'feature_example',

    // documentation (optional)...
    title: 'Example Feature',
    doc: 'A feature to demo the base API...',

    // applicability test (optional)
    isApplicable: function(){ /* ... */ },

    // feature load priority (optional)
    priority: 'medium',

    // list of feature tags to load if available (optional)
    suggested: [],

    // list of feature tags required to load before this feature (optional)
    depends: [],

    // Exclusive tag (optional)
    // NOTE: a feature can be a member of more than one exclusive group,
    //	to list more than one use an Array...
    exclusive: 'Example',

    // feature configuration (optional)
    // NOTE: if not present here this will be taken from .actions.config
    // NOTE: this takes priority over .actions.config, it is not recommended
    //	to define both.
    config: {
        option: 'value',
        // ...
    },

    // actions (optional)
    actions: Actions({
        // alternative configuration location...
        config: {
            // ...
        },
        // ...
    }),

    // action handlers (optional)
    handlers: [
        ['action.pre', 
            function(){ /* ... */ }],
        // ...
    ],
})

XXX

Meta-features

// meta-feature...
feature_set.Feature('meta-feature-tag', [
    'suggested-feature-tag',
    'other-suggested-feature-tag',
    // ...
])

XXX