Atom middle mouse scrolling hack

init.coffee

atom.workspace.observeTextEditors (item) ->
  
  # Sets up middle button scroll on the given editor component
  middleMouseScrollSetup = (editorComponent) ->
    lastClick = {x: 0, y: 0}
    lastPosition = {x: 0, y: 0}
    
    {scrollContainer} = editorComponent.refs
    
    onMouseMove = (event) ->
      [lastPosition.x, lastPosition.y] = [event.x, event.y]

    doScroll = ->
      sensitivity = 0.5

      dx = sensitivity * (lastClick.x - lastPosition.x)
      dy = sensitivity * (lastClick.y - lastPosition.y)
      
      previousScrollLeft = editorComponent.getScrollLeft()
      previousScrollTop = editorComponent.getScrollTop()

      updatedScrollLeft = previousScrollLeft - Math.round(dx)
      updatedScrollTop = previousScrollTop - Math.round(dy)

      editorComponent.setScrollLeft(updatedScrollLeft)
      editorComponent.setScrollTop(updatedScrollTop)
      
      editorComponent.updateSync()
      
    # We prevent regular scrolling on the scroll-container since it interferes with
    # the scrolling on the editor-component  
    scrollContainer.addEventListener 'scroll', (event) ->
      if process.platform is 'win32'
        scrollContainer.scrollTop = 0
        scrollContainer.scrollLeft = 0
    
    scrollContainer.addEventListener 'mousedown', (event) ->
      # click with middle button
      if event.button is 1 and process.platform is 'win32'
        [lastClick.x, lastClick.y] = [event.x, event.y]
        [lastPosition.x, lastPosition.y] = [event.x, event.y]

        intervalId = setInterval doScroll, 50

        onMouseUp = ->
          clearInterval(intervalId)
          window.removeEventListener 'mousemove', onMouseMove
          window.removeEventListener 'mouseup', onMouseUp

        window.addEventListener 'mousemove', onMouseMove
        window.addEventListener 'mouseup', onMouseUp
        
  init = () -> 
    editorView = atom.views.getView(item)
    if editorView && editorView.constructor.name == 'atom-text-editor'
      editorComponent = editorView.component
      middleMouseScrollSetup(editorComponent)
      
  init()

styles.less

.platform-win32 atom-text-editor.editor:not(.mini) {
  div {
    div.scroll-view {
      overflow: auto !important;
    }
  }

  .scroll-view::-webkit-scrollbar {
    display: none;
  }
}

Hi. I get this error in init.coffee:
Object.observe is not a function
Any idea what might cause it?

@mirkea: Sorry, didn't get a notification about the comment here.

Object.observe was deprecated, and I'm not enough of an Atom/Javascript expert to find an alternative for it at the moment.
Removing it from the script and the functionality of the script will be somewhat impaired when moving tabs around.

Uncaught TypeError: Cannot read property 'addEventListener' of undefined ???

C:\Users\phamd.atom\init.coffee:33
Hide Stack Trace
TypeError: Cannot read property 'addEventListener' of undefined
at middleMouseScrollSetup (file:///C:/Users/phamd/.atom/init.coffee:33:19)
at init (file:///C:/Users/phamd/.atom/init.coffee:54:7)
at file:///C:/Users/phamd/.atom/init.coffee:57:3
at Function.module.exports.Emitter.simpleDispatch (C:\Users\phamd\AppData\Local\atom\app-1.19.2\resources\app\node_modules\event-kit\lib\emitter.js:25:20)
at Emitter.module.exports.Emitter.emit (C:\Users\phamd\AppData\Local\atom\app-1.19.2\resources\app\node_modules\event-kit\lib\emitter.js:141:34)
at C:\Users\phamd\AppData\Local\atom\app-1.19.2\resources\app\src\workspace.js:551:30

This is all acessing private APIs and it broke after a rewrite of TextEditorComponent. Other things might break, but you should replace {scrollViewNode} = editorComponent with {scrollContainer} = editorComponent.refs.

@nathansobo

click with middle button to scroll still not working :((
Atom 1.19.2

I created a package that does this scroll-editor-on-middle-click

I've fixed the Gist to work with the newer Atom versions. Still hacky, so maybe the package linked above will be a better solution.