// Keeping the call site simple for the sake of example
const container = {
  controller : function(){
    this.tracks     = new Tracks() // Or however you want to do it
    this.showPlayer = true
  },

  view : state =>
    m( '.Container',
      m( '.Stuff' ),

      // Sub-component display is a property of the container
         this.showPlayer
      && m( TunesPlayer, {
            // Limit component input to the things it cares about,
            // saves having to share the entire application model accross all components
            track : state.tracks.selectedTrack,
            // No need to pre-define and label all possible interactions, just pass anonymous fns about
            close : () =>
              state.showPlayer = false
         } ),

      m( '.Stuff' )
    )
}

// Assuming the following is the discrete tunes-player module
const TunesPlayer = {
  // Can tell ahead of time from the signature:
  // This component has no local state, but expects input
  view : ( {}, input ) =>
    m('div', {
      // Style is not a stateful property per-instance,
      // it's just a persistent static reference
      style
    },
      m('div',
        m('button.pure-button[style="float:right"]', {
          onclick: () =>
            input.close()
        }, 'x'),

        m('div',
          // Limited concerns makes it easier to develop when the application model is in flux,
          // also allows portability to other applications that don't share a model,
          // plus limits the possibility space of what any given component can do.
          input.track.trackName
        ),

        m('small',
          m.trust('by '),

          m('cite',
            input.track.artistName
          )
        )
      ),

      m('video[controls][autoplay]', {
        src   : input.track.previewUrl,
        style : 'width: 24rem; margin: 0.5rem'
      } )
    )
}

const style = `
  z-index: 10;
  position: fixed;
  top: 50%;
  left: 50%;
  margin-left: -12em;
  margin-top: -12em;
  width: 25rem;
  border: solid 1px #bbb;
  padding: 1rem;
  background-color: white;
`