Remove all the fancy throttling of anchoring

This is premature optimization and makes things way more difficult
to reason about.

h/static/scripts/annotator/guest.coffee

@@ -149,6 +149,12 @@ module.exports = class Guest extends Annotator
   setupAnnotation: (annotation) ->
     self = this
 
+    anchors = []
+    anchoredTargets = []
+    deadHighlights = []
+
+    annotation.target ?= []
+
     locate = (target) ->
       options = {ignoreSelector: '[class^="annotator-"]'}
       return new Promise(raf)
@@ -165,32 +171,6 @@ module.exports = class Guest extends Annotator
           return anchor
       return anchor
 
-    setup = ->
-      anchors = []
-      anchoredTargets = []
-      deadHighlights = []
-
-      for anchor in self.anchors.splice(0, self.anchors.length)
-        if anchor.annotation is annotation
-          if anchor.range? and anchor.target in annotation.target
-            anchors.push(anchor)
-            anchoredTargets.push(anchor.target)
-          else if anchor.highlights?
-            deadHighlights.push(anchor.highlights)
-            delete anchor.highlights
-            delete anchor.range
-        else
-          self.anchors.push(anchor)
-
-      deadHighlights = Array::concat(deadHighlights...)
-      new Promise(raf).then(-> highlighter.removeHighlights(deadHighlights))
-
-      for target in annotation.target when target not in anchoredTargets
-        anchor = locate(target).then(highlight)
-        anchors.push(anchor)
-
-      return Promise.all(anchors)
-
     sync = (anchors) ->
       annotation.$orphan = anchors.length > 0
       for anchor in anchors
@@ -201,14 +181,26 @@ module.exports = class Guest extends Annotator
       self.plugins.BucketBar.update()
       self.plugins.CrossFrame.sync([annotation])
 
-    cleanup = ->
-      delete annotation.anchors
+    for anchor in self.anchors.splice(0, self.anchors.length)
+      if anchor.annotation is annotation
+        if anchor.range? and anchor.target in annotation.target
+          anchors.push(anchor)
+          anchoredTargets.push(anchor.target)
+        else if anchor.highlights?
+          deadHighlights.push(anchor.highlights)
+          delete anchor.highlights
+          delete anchor.range
+      else
+        self.anchors.push(anchor)
+
+    deadHighlights = Array::concat(deadHighlights...)
+    new Promise(raf).then(-> highlighter.removeHighlights(deadHighlights))
 
-    annotation.target ?= []
-    annotation.anchors ?= Promise.resolve(annotation.anchors)
-    .then(setup)
-    .then(sync)
-    .then(cleanup, cleanup)
+    for target in annotation.target when target not in anchoredTargets
+      anchor = locate(target).then(highlight)
+      anchors.push(anchor)
+
+    Promise.all(anchors).then(sync)
 
     return annotation
 

h/static/scripts/annotator/plugin/pdf.coffee

@@ -6,8 +6,6 @@ class PDF extends Annotator.Plugin
   documentLoaded: null
   observer: null
   pdfViewer: null
-  updatePromise: null
-  updateTimeout: null
 
   pluginInit: ->
     @pdfViewer = PDFViewerApplication.pdfViewer
@@ -59,50 +57,39 @@ class PDF extends Annotator.Plugin
       return {title, link}
 
   update: ->
-    self = this
     {annotator, pdfViewer} = this
 
-    _throttle = ->
-      if self.updateTimeout?
-        clearTimeout(self.updateTimeout)
-      self.updateTimeout = setTimeout(_update, 200)
+    stableAnchors = []
+    pendingAnchors = []
+    refreshAnnotations = []
 
-    _update = ->
-      anchors = []
-      annotations = []
+    for page in pdfViewer.pages when page.textLayer?.renderingDone
+      div = page.div ? page.el
+      placeholder = div.getElementsByClassName('annotator-placeholder')[0]
 
-      for page in pdfViewer.pages when page.textLayer?.renderingDone
-        div = page.div ? page.el
-        placeholder = div.getElementsByClassName('annotator-placeholder')[0]
+      switch page.renderingState
+        when RenderingStates.INITIAL
+          page.textLayer = null
+        when RenderingStates.FINISHED
+          if placeholder?
+            placeholder.parentNode.removeChild(placeholder)
 
-        switch page.renderingState
-          when RenderingStates.INITIAL
-            page.textLayer = null
-          when RenderingStates.FINISHED
-            if placeholder?
-              placeholder.parentNode.removeChild(placeholder)
+    for anchor in annotator.anchors when anchor.highlights?
+      if anchor.annotation in refreshAnnotations
+        continue
 
-      for anchor in annotator.anchors when anchor.annotation not in annotations
-        unless anchor.range? and anchor.highlights?
+      for hl in anchor.highlights
+        if not document.body.contains(hl)
+          delete anchor.highlights
           delete anchor.range
-          annotations.push(anchor.annotation)
-          continue
+          refreshAnnotations.push(anchor.annotation)
+          break
 
-        for hl in anchor.highlights
-          if not document.body.contains(hl)
-            delete anchor.range
-            annotations.push(anchor.annotation)
-            break
+    for annotation in refreshAnnotations
+      annotator.setupAnnotation(annotation)
+      pendingAnchors.push(annotation.anchors)
 
-      for annotation in annotations
-        annotator.setupAnnotation(annotation)
-        anchors.push(annotation.anchors)
-
-      self.updateTimeout = null
-      self.updatePromise = Promise.all(anchors)
-
-    @annotator.plugins.BucketBar?.update()
-    Promise.resolve(@updatePromise).then(_throttle)
+    annotator.plugins.BucketBar?.update()
 
 Annotator.Plugin.PDF = PDF