const chart = bb.generate({
    plugins: [
        new PluginA({ options }),
        new PluginB( ... ),
        ...
    ]
});

// Accesing plugin property
// [PluginA Instance, PluginB Instance, ...]
chart.plugins;

• Basically, plugin's option should be completely isolated with the main chart option value.
• The plugin instance will be reachable via .plugins property.

• The call for every phase happens once, except the rendering.
• Rendering phase, will be triggered as of chart.internal.redraw() is called.

• Every lifecycle hooks will be overridden if set.
• At the $beforeInit, will be set $$ instance variable having the current chart.internal reference, which you can access from the plugin.

// ./src/plugin/Plugin.js
class Plugin {
    constructor(options) {
        ...
    }

    // chart.internal.beforeInit()
    // - The current chart instance will be set as `$$` instance member at this hook
    $beforeInit: function(){}
    
    // chart.internal.init()
    // the 'real' ininitialization happens here
    $init: function(){}
    
    // chart.internal.afterInit()
    $afterInit: function(){}
    
    // chart.internal.redraw()
    $redraw: function(){
        // will be called every re-rendering happens
    }
    
    // chart.destroy()
    $willDestroy: function(){}
}

• Extending Plugin.js

  For all plugins are recommended(but not mandatory) to extend Plugin class (src/plugin/Plugin.js).

  If you want your plugin to be distributed with billboard.js official package, you must extend Plugin class.

  // importing from billboar.js cloned project
  import Plugin from "../Plugin";
  
  // importing from billbord.js npm package
  // import Plugin from "billboard.js/src/Plugin/Plugin";
  
  export default class MyPlugin extends Plugin {
      ...
  }

/src
    Plugin.js  # Plugin interface class
    ./PluginA   # Plugin directory
        index.js  # Plugin entry point
        ...

/dist
    ./plugin
          billboardjs-plugin-stanford.js
          billboardjs-plugin-stanford.min.js

There're 2 options on writing plugin:

• Must extend Plugins.js

  import Plugin from "../Plugin";
  
  export default class MyPlugin extends Plugin {
      ...
  }

• The source code location should be:

  • ./src/plugin/$YOUR_PLUGIN_NAME
  • The entry point file name should be index.js

  ex) The file structure for myplugin plugin

  ./src/plugin
         ./myplugin
             index.js

• An example outline of index.js

  class MyPlugin extends Plugin {
      constructor(options) {
          // plugin's option if necessary
          // calling 'super', will assign options as instance member
          super(options);
          
          // you can access options as instance member
          this.options;
  
          // NOTE:
          // Do not write business logic here, write within one of
          // lifecycle hook methods($beforeInit, $init, etc.).
          // At this point, chart isn't instantiated yet.
      }
  
      // will be executed at 'beforeInit' lifecycle
      // lifecycle hook is optional. Do not specify if isn't necessary
      $beforeInit() {
          // the current chart instance variable 'this.$$'
          // will be assigned by default as time of the initialization
          this.$$;  // access current chart instance's `chart.internal`
      }
  
      // 'init' hook (required)
      $init() {
          // write initial code for the plugin
      }
  
      // 'redraw' hook (required)
      $redraw() {
          // will be triggered as time of
          // "redraw"(resize, data toggle, etc.) happens
      }
  
      // 'willDestroy' hook (not mandatory, but highly recommended to implement)
      // will be triggered when '.destroy()' is called
      $willDestroy() {
          // write code releasing the resources used in this plugin
      }
  }

• build & dev-server

  # Running below command will facilitate on plugin development
  
  # start dev-server
  $ npm run start:plugin
  
  # build plugin
  $ npm run build:plugin

  The plugin build will be output to ./dist/plugin/billboardjs-plugin-$PLUGIN-FOLDER-NAME.

  Checkout the nightly build as an example of build:

  • https://github.com/naver/billboard.js/tree/nightly/dist/plugin

As an example, take a look on below plugins implementation from master.

• Stanford Diagram Plugin (Demo)
• Text Overlap Plugin (Demo)

Basically, there's no any restriction (except lifecycle hook) if you opt develop as an independent plugin.

import Plugin from "billboard.js/src/Plugin/Plugin";

export default class MyPlugin extends Plugin {
    ...
}

The package name for plugin can be any, but to be distinguished is recommended put billboardjs-plugin- as prefix.

billboardjs-plugin-$PLUGIN-NAME