diff --git a/src/ol/Collection.js b/src/ol/Collection.js
index bca2a49ba8..8e8abff5a8 100644
--- a/src/ol/Collection.js
+++ b/src/ol/Collection.js
@@ -115,8 +115,7 @@ Collection.prototype.clear = function() {
  * @api
  */
 Collection.prototype.extend = function(arr) {
-  let i, ii;
-  for (i = 0, ii = arr.length; i < ii; ++i) {
+  for (let i = 0, ii = arr.length; i < ii; ++i) {
     this.push(arr[i]);
   }
   return this;
@@ -225,8 +224,7 @@ Collection.prototype.push = function(elem) {
  */
 Collection.prototype.remove = function(elem) {
   const arr = this.array_;
-  let i, ii;
-  for (i = 0, ii = arr.length; i < ii; ++i) {
+  for (let i = 0, ii = arr.length; i < ii; ++i) {
     if (arr[i] === elem) {
       return this.removeAt(i);
     }
@@ -270,8 +268,7 @@ Collection.prototype.setAt = function(index, elem) {
     this.dispatchEvent(
       new CollectionEvent(CollectionEventType.ADD, elem));
   } else {
-    let j;
-    for (j = n; j < index; ++j) {
+    for (let j = n; j < index; ++j) {
       this.insertAt(j, undefined);
     }
     this.insertAt(index, elem);
diff --git a/src/ol/pointer/PointerEventHandler.js b/src/ol/pointer/PointerEventHandler.js
index bd3f004fc2..588d168e8e 100644
--- a/src/ol/pointer/PointerEventHandler.js
+++ b/src/ol/pointer/PointerEventHandler.js
@@ -172,9 +172,8 @@ PointerEventHandler.prototype.registerSource = function(name, source) {
  */
 PointerEventHandler.prototype.register_ = function() {
   const l = this.eventSourceList_.length;
-  let eventSource;
   for (let i = 0; i < l; i++) {
-    eventSource = this.eventSourceList_[i];
+    const eventSource = this.eventSourceList_[i];
     this.addEvents_(eventSource.getEvents());
   }
 };
@@ -186,9 +185,8 @@ PointerEventHandler.prototype.register_ = function() {
  */
 PointerEventHandler.prototype.unregister_ = function() {
   const l = this.eventSourceList_.length;
-  let eventSource;
   for (let i = 0; i < l; i++) {
-    eventSource = this.eventSourceList_[i];
+    const eventSource = this.eventSourceList_[i];
     this.removeEvents_(eventSource.getEvents());
   }
 };
diff --git a/src/ol/pointer/TouchSource.js b/src/ol/pointer/TouchSource.js
index 24be859017..6aedb98c82 100644
--- a/src/ol/pointer/TouchSource.js
+++ b/src/ol/pointer/TouchSource.js
@@ -219,9 +219,8 @@ TouchSource.prototype.processTouches_ = function(inEvent, inFunction) {
   function preventDefault() {
     inEvent.preventDefault();
   }
-  let i, pointer;
-  for (i = 0; i < count; ++i) {
-    pointer = this.touchToPointer_(inEvent, touches[i]);
+  for (let i = 0; i < count; ++i) {
+    const pointer = this.touchToPointer_(inEvent, touches[i]);
     // forward touch preventDefaults
     pointer.preventDefault = preventDefault;
     inFunction.call(this, inEvent, pointer);
@@ -237,9 +236,8 @@ TouchSource.prototype.processTouches_ = function(inEvent, inFunction) {
  */
 TouchSource.prototype.findTouch_ = function(touchList, searchId) {
   const l = touchList.length;
-  let touch;
   for (let i = 0; i < l; i++) {
-    touch = touchList[i];
+    const touch = touchList[i];
     if (touch.identifier === searchId) {
       return true;
     }
@@ -267,10 +265,9 @@ TouchSource.prototype.vacuumTouches_ = function(inEvent) {
   const count = keys.length;
   if (count >= touchList.length) {
     const d = [];
-    let i, key, value;
-    for (i = 0; i < count; ++i) {
-      key = keys[i];
-      value = this.pointerMap[key];
+    for (let i = 0; i < count; ++i) {
+      const key = keys[i];
+      const value = this.pointerMap[key];
       // Never remove pointerId == 1, which is mouse.
       // Touch identifiers are 2 smaller than their pointerId, which is the
       // index in pointermap.
@@ -279,7 +276,7 @@ TouchSource.prototype.vacuumTouches_ = function(inEvent) {
         d.push(value.out);
       }
     }
-    for (i = 0; i < d.length; ++i) {
+    for (let i = 0; i < d.length; ++i) {
       this.cancelOut_(inEvent, d[i]);
     }
   }
diff --git a/src/ol/proj.js b/src/ol/proj.js
index e2633575b0..42e2ea8f0a 100644
--- a/src/ol/proj.js
+++ b/src/ol/proj.js
@@ -317,12 +317,11 @@ export function createTransformFromCoordinateTransform(coordTransform) {
       const length = input.length;
       const dimension = opt_dimension !== undefined ? opt_dimension : 2;
       const output = opt_output !== undefined ? opt_output : new Array(length);
-      let point, i, j;
-      for (i = 0; i < length; i += dimension) {
-        point = coordTransform([input[i], input[i + 1]]);
+      for (let i = 0; i < length; i += dimension) {
+        const point = coordTransform([input[i], input[i + 1]]);
         output[i] = point[0];
         output[i + 1] = point[1];
-        for (j = dimension - 1; j >= 2; --j) {
+        for (let j = dimension - 1; j >= 2; --j) {
           output[i + j] = input[i + j];
         }
       }