en/builder/src/echarts3/component/legend.js

// Do not contain scrollable legend, for sake of file size.
import * as echarts from '../echarts';
import './legend/LegendModel';
import './legend/legendAction';
import './legend/LegendView';
import legendFilter from './legend/legendFilter';
import Component from '../model/Component'; // Series Filter

echarts.registerProcessor(legendFilter);
Component.registerSubTypeDefaulter('legend', function () {
  // Default 'plain' when no type specified.
  return 'plain';
});