Lucy Live

Part of lucidity project.

Live coding support for node.js

Replace require by live.require to update the required code or assets as the source file changes.

Installation

npm install lucy-live --save

Usage example

const live = require ( 'lucy-live' )

// expects foo.js library to return "obj"
live.load
( 'foo.js'
, function ( obj )
  {
    console.log ( 'foo changed: ' + obj )
  }
)

live.path
( 'image.jpg'
, function ( imgPath )
  { // do something with new image taking
    // care of Browser cache
  }
)

// Start listening for changes in '.'
live.watch ( '.' )

The module definition needs to take into account that it may be reloaded by reusing module.exports and updating it. Simply exporting a new module will not work because the newly created module will not be linked to existing objects.

Example of a module exporting a simple Person class where methods are live coded. The code shown here is just one way to implement this behaviour. The only thing to notice is that loaded is false on first load and true on reload:

// Person.js

if ( ! exports.loaded )
{ // Initial code loading is used to create a simple function wrapping a call
  // to an initialize method.
  module.exports = function ()
  { this.init.apply ( arguments )
  }
}
// Code from here is executed on every file change.
const Person = module.exports.prototype

Person.init = function ( name )
{ this._name = name
}

Person.sayHello = function ()
{ console.log ( `Hello, I am ${ this._name }.` )
}

Person usage:

const live   = require ( 'lucy-live' )
const Person = live.require ( './Person' )

let o = new Person ( 'Georg Groddeck' )
o.sayHello ()

setTimeout
( function ()
  { o.sayHello () // will call the updated 'sayHello' method
  }               // when Person.js is changed
, 2
)

// To only call a method when the file is loaded (always called at least once)
// one can use live.path:
live.path
( './Person'
, function ( path )
  { console.log ( `Path '${ path }' changed.` )
    o.sayHello ()
  }
)

// Start watching for changes in this file's directory.
live.watch ( '.' )

Real world example of GLSL shader live coding (taken from Lucidity.

const ShaderEffect = require ( 'lucy-compose' ).ShaderEffect
const THREE = require ( 'three' )
const live  = require ( 'lucy-live' )

if (!exports.loaded) {
  // On first load, we create the effect
  module.exports = new ShaderEffect
}
const self = module.exports

// We simply update the shaders when the glsl files change.

live.read
( './vert.glsl'
, function ( s )
  { self.material.vertexShader = s
    self.material.needsUpdate  = true
  }
)

live.read
( './frag.glsl'
, function ( s )
  { self.material.fragmentShader = s
   self.material.needsUpdate    = true
  }
)

// We could customize a method like this:
self.render = function ( context, target )
{
  // ...
}

Tests

npm test

Contributing

Please use 'jessy style'.

Add unit tests for any new or changed functionality.

Release History

• 0.1.3 (2015-09-22) Better documentation.
• 0.1.2 (2015-09-22) Compatible with latest version of node.js.
• 0.1.1 (2015-09-02) NPM readme fix.
• 0.1.0 (2015-09-02) Initial release.