def source

@source ||= findController type: RubyController,

element: document.querySelector(element.dataset.source)

end

async def setup()

await codemirror_ready

# create another editor below the output

@outputDiv = document.createElement('div')

@outputDiv.classList.add('editor', 'js')

element.appendChild(@outputDiv)

@jsEditor = CodeMirror.jsEditor(@outputDiv)

@jspre = element.querySelector('pre.js')

if @jspre

contents = @jspre.value

else

@jspre = document.createElement('pre')

@jspre.classList.add 'js'

element.appendChild(@jspre)

# set initial contents from markdown code area, then hide the code

nextSibling = element.nextElementSibling

if nextSibling and nextSibling.classList.contains('language-js')

contents = nextSibling.textContent.rstrip()

nextSibling.style.display = 'none'

end

end

element.style.display = 'block'

end

# update contents

def contents=(script)

return unless @jsEditor

@jsEditor.dispatch(

changes: {from: 0, to: @jsEditor.state.doc.length, insert: script}

)

@jspre.classList.remove 'exception'

@jspre.style.display = 'none'

@outputDiv.style.display = 'block'

end

# display an error

def exception=(message)

return unless @jsEditor

@jspre.textContent = message

@jspre.classList.add 'exception'

@jspre.style.display = 'block'

@outputDiv.style.display = 'none'

end

# remove editor on disconnect

def teardown()

element.querySelector('.editor.js').remove()

end