diff --git a/spec/decoration-manager-spec.coffee b/spec/decoration-manager-spec.coffee
index e57660a57..ba5de0cf2 100644
--- a/spec/decoration-manager-spec.coffee
+++ b/spec/decoration-manager-spec.coffee
@@ -14,8 +14,7 @@ describe "DecorationManager", ->
       atom.packages.activatePackage('language-javascript')
 
   afterEach ->
-    decorationManager.destroy()
-    buffer.release()
+    buffer.destroy()
 
   describe "decorations", ->
     [layer1Marker, layer2Marker, layer1MarkerDecoration, layer2MarkerDecoration, decorationProperties] = []
diff --git a/src/decoration-manager.coffee b/src/decoration-manager.coffee
deleted file mode 100644
index 05935f018..000000000
--- a/src/decoration-manager.coffee
+++ /dev/null
@@ -1,191 +0,0 @@
-{Emitter} = require 'event-kit'
-Model = require './model'
-Decoration = require './decoration'
-LayerDecoration = require './layer-decoration'
-
-module.exports =
-class DecorationManager extends Model
-  didUpdateDecorationsEventScheduled: false
-  updatedSynchronously: false
-
-  constructor: (@displayLayer) ->
-    super
-
-    @emitter = new Emitter
-    @decorationsById = {}
-    @decorationsByMarkerId = {}
-    @overlayDecorationsById = {}
-    @layerDecorationsByMarkerLayerId = {}
-    @decorationCountsByLayerId = {}
-    @layerUpdateDisposablesByLayerId = {}
-
-  observeDecorations: (callback) ->
-    callback(decoration) for decoration in @getDecorations()
-    @onDidAddDecoration(callback)
-
-  onDidAddDecoration: (callback) ->
-    @emitter.on 'did-add-decoration', callback
-
-  onDidRemoveDecoration: (callback) ->
-    @emitter.on 'did-remove-decoration', callback
-
-  onDidUpdateDecorations: (callback) ->
-    @emitter.on 'did-update-decorations', callback
-
-  setUpdatedSynchronously: (@updatedSynchronously) ->
-
-  decorationForId: (id) ->
-    @decorationsById[id]
-
-  getDecorations: (propertyFilter) ->
-    allDecorations = []
-    for markerId, decorations of @decorationsByMarkerId
-      allDecorations.push(decorations...) if decorations?
-    if propertyFilter?
-      allDecorations = allDecorations.filter (decoration) ->
-        for key, value of propertyFilter
-          return false unless decoration.properties[key] is value
-        true
-    allDecorations
-
-  getLineDecorations: (propertyFilter) ->
-    @getDecorations(propertyFilter).filter (decoration) -> decoration.isType('line')
-
-  getLineNumberDecorations: (propertyFilter) ->
-    @getDecorations(propertyFilter).filter (decoration) -> decoration.isType('line-number')
-
-  getHighlightDecorations: (propertyFilter) ->
-    @getDecorations(propertyFilter).filter (decoration) -> decoration.isType('highlight')
-
-  getOverlayDecorations: (propertyFilter) ->
-    result = []
-    for id, decoration of @overlayDecorationsById
-      result.push(decoration)
-    if propertyFilter?
-      result.filter (decoration) ->
-        for key, value of propertyFilter
-          return false unless decoration.properties[key] is value
-        true
-    else
-      result
-
-  decorationsForScreenRowRange: (startScreenRow, endScreenRow) ->
-    decorationsByMarkerId = {}
-    for layerId of @decorationCountsByLayerId
-      layer = @displayLayer.getMarkerLayer(layerId)
-      for marker in layer.findMarkers(intersectsScreenRowRange: [startScreenRow, endScreenRow])
-        if decorations = @decorationsByMarkerId[marker.id]
-          decorationsByMarkerId[marker.id] = decorations
-    decorationsByMarkerId
-
-  decorationsStateForScreenRowRange: (startScreenRow, endScreenRow) ->
-    decorationsState = {}
-
-    for layerId of @decorationCountsByLayerId
-      layer = @displayLayer.getMarkerLayer(layerId)
-
-      for marker in layer.findMarkers(intersectsScreenRowRange: [startScreenRow, endScreenRow]) when marker.isValid()
-        screenRange = marker.getScreenRange()
-        bufferRange = marker.getBufferRange()
-        rangeIsReversed = marker.isReversed()
-
-        if decorations = @decorationsByMarkerId[marker.id]
-          for decoration in decorations
-            decorationsState[decoration.id] = {
-              properties: decoration.properties
-              screenRange, bufferRange, rangeIsReversed
-            }
-
-        if layerDecorations = @layerDecorationsByMarkerLayerId[layerId]
-          for layerDecoration in layerDecorations
-            decorationsState["#{layerDecoration.id}-#{marker.id}"] = {
-              properties: layerDecoration.overridePropertiesByMarkerId[marker.id] ? layerDecoration.properties
-              screenRange, bufferRange, rangeIsReversed
-            }
-
-    decorationsState
-
-  decorateMarker: (marker, decorationParams) ->
-    if marker.isDestroyed()
-      error = new Error("Cannot decorate a destroyed marker")
-      error.metadata = {markerLayerIsDestroyed: marker.layer.isDestroyed()}
-      if marker.destroyStackTrace?
-        error.metadata.destroyStackTrace = marker.destroyStackTrace
-      if marker.bufferMarker?.destroyStackTrace?
-        error.metadata.destroyStackTrace = marker.bufferMarker?.destroyStackTrace
-      throw error
-    marker = @displayLayer.getMarkerLayer(marker.layer.id).getMarker(marker.id)
-    decoration = new Decoration(marker, this, decorationParams)
-    @decorationsByMarkerId[marker.id] ?= []
-    @decorationsByMarkerId[marker.id].push(decoration)
-    @overlayDecorationsById[decoration.id] = decoration if decoration.isType('overlay')
-    @decorationsById[decoration.id] = decoration
-    @observeDecoratedLayer(marker.layer)
-    @scheduleUpdateDecorationsEvent()
-    @emitter.emit 'did-add-decoration', decoration
-    decoration
-
-  decorateMarkerLayer: (markerLayer, decorationParams) ->
-    throw new Error("Cannot decorate a destroyed marker layer") if markerLayer.isDestroyed()
-    decoration = new LayerDecoration(markerLayer, this, decorationParams)
-    @layerDecorationsByMarkerLayerId[markerLayer.id] ?= []
-    @layerDecorationsByMarkerLayerId[markerLayer.id].push(decoration)
-    @observeDecoratedLayer(markerLayer)
-    @scheduleUpdateDecorationsEvent()
-    decoration
-
-  decorationsForMarkerId: (markerId) ->
-    @decorationsByMarkerId[markerId]
-
-  scheduleUpdateDecorationsEvent: ->
-    if @updatedSynchronously
-      @emitter.emit 'did-update-decorations'
-      return
-
-    unless @didUpdateDecorationsEventScheduled
-      @didUpdateDecorationsEventScheduled = true
-      process.nextTick =>
-        @didUpdateDecorationsEventScheduled = false
-        @emitter.emit 'did-update-decorations'
-
-  decorationDidChangeType: (decoration) ->
-    if decoration.isType('overlay')
-      @overlayDecorationsById[decoration.id] = decoration
-    else
-      delete @overlayDecorationsById[decoration.id]
-
-  didDestroyMarkerDecoration: (decoration) ->
-    {marker} = decoration
-    return unless decorations = @decorationsByMarkerId[marker.id]
-    index = decorations.indexOf(decoration)
-
-    if index > -1
-      decorations.splice(index, 1)
-      delete @decorationsById[decoration.id]
-      @emitter.emit 'did-remove-decoration', decoration
-      delete @decorationsByMarkerId[marker.id] if decorations.length is 0
-      delete @overlayDecorationsById[decoration.id]
-      @unobserveDecoratedLayer(marker.layer)
-    @scheduleUpdateDecorationsEvent()
-
-  didDestroyLayerDecoration: (decoration) ->
-    {markerLayer} = decoration
-    return unless decorations = @layerDecorationsByMarkerLayerId[markerLayer.id]
-    index = decorations.indexOf(decoration)
-
-    if index > -1
-      decorations.splice(index, 1)
-      delete @layerDecorationsByMarkerLayerId[markerLayer.id] if decorations.length is 0
-      @unobserveDecoratedLayer(markerLayer)
-    @scheduleUpdateDecorationsEvent()
-
-  observeDecoratedLayer: (layer) ->
-    @decorationCountsByLayerId[layer.id] ?= 0
-    if ++@decorationCountsByLayerId[layer.id] is 1
-      @layerUpdateDisposablesByLayerId[layer.id] = layer.onDidUpdate(@scheduleUpdateDecorationsEvent.bind(this))
-
-  unobserveDecoratedLayer: (layer) ->
-    if --@decorationCountsByLayerId[layer.id] is 0
-      @layerUpdateDisposablesByLayerId[layer.id].dispose()
-      delete @decorationCountsByLayerId[layer.id]
-      delete @layerUpdateDisposablesByLayerId[layer.id]
diff --git a/src/decoration-manager.js b/src/decoration-manager.js
new file mode 100644
index 000000000..f9e31e60d
--- /dev/null
+++ b/src/decoration-manager.js
@@ -0,0 +1,272 @@
+const {Emitter} = require('event-kit')
+const Decoration = require('./decoration')
+const LayerDecoration = require('./layer-decoration')
+
+module.exports =
+class DecorationManager {
+  constructor(displayLayer) {
+    this.displayLayer = displayLayer
+
+    this.emitter = new Emitter
+    this.didUpdateDecorationsEventScheduled = false
+    this.updatedSynchronously = false
+    this.decorationsById = {}
+    this.decorationsByMarkerId = {}
+    this.overlayDecorationsById = {}
+    this.layerDecorationsByMarkerLayerId = {}
+    this.decorationCountsByLayerId = {}
+    this.layerUpdateDisposablesByLayerId = {}
+  }
+
+  observeDecorations(callback) {
+    for (let decoration of this.getDecorations()) { callback(decoration); }
+    return this.onDidAddDecoration(callback)
+  }
+
+  onDidAddDecoration(callback) {
+    return this.emitter.on('did-add-decoration', callback)
+  }
+
+  onDidRemoveDecoration(callback) {
+    return this.emitter.on('did-remove-decoration', callback)
+  }
+
+  onDidUpdateDecorations(callback) {
+    return this.emitter.on('did-update-decorations', callback)
+  }
+
+  setUpdatedSynchronously(updatedSynchronously) {
+    this.updatedSynchronously = updatedSynchronously
+  }
+
+  decorationForId(id) {
+    return this.decorationsById[id]
+  }
+
+  getDecorations(propertyFilter) {
+    let allDecorations = []
+    for (let markerId in this.decorationsByMarkerId) {
+      const decorations = this.decorationsByMarkerId[markerId]
+      if (decorations != null) {
+        allDecorations.push(...decorations)
+      }
+    }
+    if (propertyFilter != null) {
+      allDecorations = allDecorations.filter(function(decoration) {
+        for (let key in propertyFilter) {
+          const value = propertyFilter[key]
+          if (decoration.properties[key] !== value) return false
+        }
+        return true
+      })
+    }
+    return allDecorations
+  }
+
+  getLineDecorations(propertyFilter) {
+    return this.getDecorations(propertyFilter).filter(decoration => decoration.isType('line'))
+  }
+
+  getLineNumberDecorations(propertyFilter) {
+    return this.getDecorations(propertyFilter).filter(decoration => decoration.isType('line-number'))
+  }
+
+  getHighlightDecorations(propertyFilter) {
+    return this.getDecorations(propertyFilter).filter(decoration => decoration.isType('highlight'))
+  }
+
+  getOverlayDecorations(propertyFilter) {
+    const result = []
+    for (let id in this.overlayDecorationsById) {
+      const decoration = this.overlayDecorationsById[id]
+      result.push(decoration)
+    }
+    if (propertyFilter != null) {
+      return result.filter(function(decoration) {
+        for (let key in propertyFilter) {
+          const value = propertyFilter[key]
+          if (decoration.properties[key] !== value) {
+            return false
+          }
+        }
+        return true
+      })
+    } else {
+      return result
+    }
+  }
+
+  decorationsForScreenRowRange(startScreenRow, endScreenRow) {
+    const decorationsByMarkerId = {}
+    for (let layerId in this.decorationCountsByLayerId) {
+      const layer = this.displayLayer.getMarkerLayer(layerId)
+      for (let marker of layer.findMarkers({intersectsScreenRowRange: [startScreenRow, endScreenRow]})) {
+        const decorations = this.decorationsByMarkerId[marker.id]
+        if (decorations) {
+          decorationsByMarkerId[marker.id] = decorations
+        }
+      }
+    }
+    return decorationsByMarkerId
+  }
+
+  decorationsStateForScreenRowRange(startScreenRow, endScreenRow) {
+    const decorationsState = {}
+
+    for (let layerId in this.decorationCountsByLayerId) {
+      const layer = this.displayLayer.getMarkerLayer(layerId)
+
+      for (let marker of layer.findMarkers({intersectsScreenRowRange: [startScreenRow, endScreenRow]})) {
+        if (marker.isValid()) {
+          const screenRange = marker.getScreenRange()
+          const bufferRange = marker.getBufferRange()
+          const rangeIsReversed = marker.isReversed()
+
+          const decorations = this.decorationsByMarkerId[marker.id]
+          if (decorations) {
+            for (let decoration of decorations) {
+              decorationsState[decoration.id] = {
+                properties: decoration.properties,
+                screenRange, bufferRange, rangeIsReversed
+              }
+            }
+          }
+
+          const layerDecorations = this.layerDecorationsByMarkerLayerId[layerId]
+          if (layerDecorations) {
+            for (let layerDecoration of layerDecorations) {
+              decorationsState[`${layerDecoration.id}-${marker.id}`] = {
+                properties: layerDecoration.overridePropertiesByMarkerId[marker.id] != null ? layerDecoration.overridePropertiesByMarkerId[marker.id] : layerDecoration.properties,
+                screenRange, bufferRange, rangeIsReversed
+              }
+            }
+          }
+        }
+      }
+    }
+
+    return decorationsState
+  }
+
+  decorateMarker(marker, decorationParams) {
+    if (marker.isDestroyed()) {
+      const error = new Error("Cannot decorate a destroyed marker")
+      error.metadata = {markerLayerIsDestroyed: marker.layer.isDestroyed()}
+      if (marker.destroyStackTrace != null) {
+        error.metadata.destroyStackTrace = marker.destroyStackTrace
+      }
+      if (marker.bufferMarker != null && marker.bufferMarker.destroyStackTrace != null) {
+        error.metadata.destroyStackTrace = marker.bufferMarker.destroyStackTrace
+      }
+      throw error
+    }
+    marker = this.displayLayer.getMarkerLayer(marker.layer.id).getMarker(marker.id)
+    const decoration = new Decoration(marker, this, decorationParams)
+    if (this.decorationsByMarkerId[marker.id] == null) {
+      this.decorationsByMarkerId[marker.id] = []
+    }
+    this.decorationsByMarkerId[marker.id].push(decoration)
+    if (decoration.isType('overlay')) {
+      this.overlayDecorationsById[decoration.id] = decoration
+    }
+    this.decorationsById[decoration.id] = decoration
+    this.observeDecoratedLayer(marker.layer)
+    this.scheduleUpdateDecorationsEvent()
+    this.emitter.emit('did-add-decoration', decoration)
+    return decoration
+  }
+
+  decorateMarkerLayer(markerLayer, decorationParams) {
+    if (markerLayer.isDestroyed()) {
+      throw new Error("Cannot decorate a destroyed marker layer")
+    }
+    const decoration = new LayerDecoration(markerLayer, this, decorationParams)
+    if (this.layerDecorationsByMarkerLayerId[markerLayer.id] == null) {
+      this.layerDecorationsByMarkerLayerId[markerLayer.id] = []
+    }
+    this.layerDecorationsByMarkerLayerId[markerLayer.id].push(decoration)
+    this.observeDecoratedLayer(markerLayer)
+    this.scheduleUpdateDecorationsEvent()
+    return decoration
+  }
+
+  decorationsForMarkerId(markerId) {
+    return this.decorationsByMarkerId[markerId]
+  }
+
+  scheduleUpdateDecorationsEvent() {
+    if (this.updatedSynchronously) {
+      this.emitter.emit('did-update-decorations')
+      return
+    }
+
+    if (!this.didUpdateDecorationsEventScheduled) {
+      this.didUpdateDecorationsEventScheduled = true
+      return process.nextTick(() => {
+        this.didUpdateDecorationsEventScheduled = false
+        return this.emitter.emit('did-update-decorations')
+      }
+      )
+    }
+  }
+
+  decorationDidChangeType(decoration) {
+    if (decoration.isType('overlay')) {
+      return this.overlayDecorationsById[decoration.id] = decoration
+    } else {
+      return delete this.overlayDecorationsById[decoration.id]
+    }
+  }
+
+  didDestroyMarkerDecoration(decoration) {
+    let decorations
+    const {marker} = decoration
+    if (!(decorations = this.decorationsByMarkerId[marker.id])) return
+    const index = decorations.indexOf(decoration)
+
+    if (index > -1) {
+      decorations.splice(index, 1)
+      delete this.decorationsById[decoration.id]
+      this.emitter.emit('did-remove-decoration', decoration)
+      if (decorations.length === 0) {
+        delete this.decorationsByMarkerId[marker.id]
+      }
+      delete this.overlayDecorationsById[decoration.id]
+      this.unobserveDecoratedLayer(marker.layer)
+    }
+    return this.scheduleUpdateDecorationsEvent()
+  }
+
+  didDestroyLayerDecoration(decoration) {
+    let decorations
+    const {markerLayer} = decoration
+    if (!(decorations = this.layerDecorationsByMarkerLayerId[markerLayer.id])) return
+    const index = decorations.indexOf(decoration)
+
+    if (index > -1) {
+      decorations.splice(index, 1)
+      if (decorations.length === 0) {
+        delete this.layerDecorationsByMarkerLayerId[markerLayer.id]
+      }
+      this.unobserveDecoratedLayer(markerLayer)
+    }
+    return this.scheduleUpdateDecorationsEvent()
+  }
+
+  observeDecoratedLayer(layer) {
+    if (this.decorationCountsByLayerId[layer.id] == null) {
+      this.decorationCountsByLayerId[layer.id] = 0
+    }
+    if (++this.decorationCountsByLayerId[layer.id] === 1) {
+      this.layerUpdateDisposablesByLayerId[layer.id] = layer.onDidUpdate(this.scheduleUpdateDecorationsEvent.bind(this))
+    }
+  }
+
+  unobserveDecoratedLayer(layer) {
+    if (--this.decorationCountsByLayerId[layer.id] === 0) {
+      this.layerUpdateDisposablesByLayerId[layer.id].dispose()
+      delete this.decorationCountsByLayerId[layer.id]
+      delete this.layerUpdateDisposablesByLayerId[layer.id]
+    }
+  }
+}