Use blocked scoped variables

In addition to using const and let, this also upgrades our linter config and removes lint (mostly whitespace).

src/ol/TileQueue.js

@@ -16,24 +16,24 @@ import PriorityQueue from './structs/PriorityQueue.js';
  *     Function called on each tile change event.
  * @struct
  */
-var TileQueue = function(tilePriorityFunction, tileChangeCallback) {
+const TileQueue = function(tilePriorityFunction, tileChangeCallback) {
 
   PriorityQueue.call(
-      this,
-      /**
+    this,
+    /**
        * @param {Array} element Element.
        * @return {number} Priority.
        */
-      function(element) {
-        return tilePriorityFunction.apply(null, element);
-      },
-      /**
+    function(element) {
+      return tilePriorityFunction.apply(null, element);
+    },
+    /**
        * @param {Array} element Element.
        * @return {string} Key.
        */
-      function(element) {
-        return /** @type {ol.Tile} */ (element[0]).getKey();
-      });
+    function(element) {
+      return /** @type {ol.Tile} */ (element[0]).getKey();
+    });
 
   /**
    * @private
@@ -62,11 +62,11 @@ inherits(TileQueue, PriorityQueue);
  * @inheritDoc
  */
 TileQueue.prototype.enqueue = function(element) {
-  var added = PriorityQueue.prototype.enqueue.call(this, element);
+  const added = PriorityQueue.prototype.enqueue.call(this, element);
   if (added) {
-    var tile = element[0];
+    const tile = element[0];
     _ol_events_.listen(tile, EventType.CHANGE,
-        this.handleTileChange, this);
+      this.handleTileChange, this);
   }
   return added;
 };
@@ -85,13 +85,13 @@ TileQueue.prototype.getTilesLoading = function() {
  * @protected
  */
 TileQueue.prototype.handleTileChange = function(event) {
-  var tile = /** @type {ol.Tile} */ (event.target);
-  var state = tile.getState();
+  const tile = /** @type {ol.Tile} */ (event.target);
+  const state = tile.getState();
   if (state === TileState.LOADED || state === TileState.ERROR ||
       state === TileState.EMPTY || state === TileState.ABORT) {
     _ol_events_.unlisten(tile, EventType.CHANGE,
-        this.handleTileChange, this);
-    var tileKey = tile.getKey();
+      this.handleTileChange, this);
+    const tileKey = tile.getKey();
     if (tileKey in this.tilesLoadingKeys_) {
       delete this.tilesLoadingKeys_[tileKey];
       --this.tilesLoading_;
@@ -106,9 +106,9 @@ TileQueue.prototype.handleTileChange = function(event) {
  * @param {number} maxNewLoads Maximum number of new tiles to load.
  */
 TileQueue.prototype.loadMoreTiles = function(maxTotalLoading, maxNewLoads) {
-  var newLoads = 0;
-  var abortedTiles = false;
-  var state, tile, tileKey;
+  let newLoads = 0;
+  let abortedTiles = false;
+  let state, tile, tileKey;
   while (this.tilesLoading_ < maxTotalLoading && newLoads < maxNewLoads &&
          this.getCount() > 0) {
     tile = /** @type {ol.Tile} */ (this.dequeue()[0]);