ES6 Hookable class

Hookable.js

/*
  Note: handy class to extend when you want a dead simple hook cycle system for anything you'll want to make 
  triggerable.
  
  usage:
  
  const Hookable = require('./path/to/Hookable...');
  
  class SomeClass extends Hookable {
  
    constructor() {
      super();
      
      // define the hooks as an object with empty arrays
      this.hooks = {
        'trigger': []
      }
      
    }
    
    // dispatching hook cycles within the class
    awesomeMethod() {
      this.dispatchHook('trigger', {
        foo: 'bar',
        hello: 'world'
      });
    }
    
  }
  
  // subscribe to hooks:
  let hookie = new SomeClass();
  
  hookie.on('trigger', data => {
    console.log(data.foo);
  }).on('trigger', data => {
    console.log(data.hello);
  });
  
  // now call the method that will dispatch the trigger event:
  hookie.awesomeMethod(); // => 'bar', 'world'
  
 */

// empty function placeholder
const noop = () => true;

// hookable class wrapper
module.exports = class Hookable {

  constructor() {
    this.hooks = {};
  }

  // subscribes a hook
  on(evt, cb = noop) {
    // create hook entry
    if(!this.hooks[evt]) this.hooks[evt] = [];
    this.hooks[evt].push(cb);
    return this;
  }

  // runs a hook cycle
  dispatchHook(evt = '', data = {}) {
    if(this.hooks[evt]) {
      this.hooks[evt].forEach(hook => {
        if(hook instanceof Function) {
          hook.call(this, data);
        }
      });
    }
    return this;
  }

}