calendar.es6.js

const calendar = {
  controller : ( date = moment() ) => {
    const weeks   = []
    const end     = date.endOf( 'month' ).startOf( 'week' )

    let   current = date.startOf( 'month' ).startOf( 'week' )
    
    do {
      weeks.push( {
        start : current.clone()
      } )

      current = current.add( 1, 'week' )
    }
    while( 
      current.isBefore( end ) 
    )

    return { weeks }
  },
  
  view : ctrl =>
    m( `.month[style="
      display        : flex;
      align-items    : stretch;
      flex-direction : column;
    "]`,

      ctrl.weeks.map( week =>
        m( `.week["
          display     : flex;
          align-items : stretch;
        "]`, 
          
          ( new Array( 7 ) ).fill( 0 )
            .map( ( _, index ) =>
              m( `.day["
                display        : flex;
                align-items    : stretch;
                flex-direction : column;
              "]`, 

                m( '.label',
                  week.start.add( index, 'days' ).calendar()
                )
              )
            )
        )
      )
    )
}

m.mount( document.body, {
	view : () =>
  	m( `.app[style="
    	position : fixed;
      width    : 100%;
      height   : 100%;
    "]` ),
    
    m( calendar )
} )