diff --git a/src/js/utils/browser.js b/src/js/utils/browser.js
index 384517fb53..cdd41692f0 100644
--- a/src/js/utils/browser.js
+++ b/src/js/utils/browser.js
@@ -199,8 +199,9 @@ if (!IS_CHROMIUM) {
     const minor = match[2] && parseFloat(match[2]);
 
     if (major && minor) {
-      return parseFloat(match[1] + '.' + match[2]);
-    } else if (major) {
+      return parseFloat(`${match[1]}.${match[2]}`);
+    }
+    if (major) {
       return major;
     }
     return null;
diff --git a/src/js/utils/buffer.js b/src/js/utils/buffer.js
index 8e5c18585f..c03c775fab 100644
--- a/src/js/utils/buffer.js
+++ b/src/js/utils/buffer.js
@@ -18,8 +18,6 @@ import { createTimeRange } from './time.js';
  */
 export function bufferedPercent(buffered, duration) {
   let bufferedDuration = 0;
-  let start;
-  let end;
 
   if (!duration) {
     return 0;
@@ -30,13 +28,9 @@ export function bufferedPercent(buffered, duration) {
   }
 
   for (let i = 0; i < buffered.length; i++) {
-    start = buffered.start(i);
-    end = buffered.end(i);
-
+    const start = buffered.start(i);
     // buffered end can be bigger than duration by a very small fraction
-    if (end > duration) {
-      end = duration;
-    }
+    const end = Math.min(buffered.end(i), duration);
 
     bufferedDuration += end - start;
   }
diff --git a/src/js/utils/events.js b/src/js/utils/events.js
index 4945c236b0..0f36720b1d 100644
--- a/src/js/utils/events.js
+++ b/src/js/utils/events.js
@@ -305,12 +305,11 @@ export function on(elem, type, fn) {
         for (let m = 0, n = handlersCopy.length; m < n; m++) {
           if (event.isImmediatePropagationStopped()) {
             break;
-          } else {
-            try {
-              handlersCopy[m].call(elem, event, hash);
-            } catch (e) {
-              log.error(e);
-            }
+          }
+          try {
+            handlersCopy[m].call(elem, event, hash);
+          } catch (e) {
+            log.error(e);
           }
         }
       }
diff --git a/src/js/utils/filter-source.js b/src/js/utils/filter-source.js
index 7cfe021206..f78ca2329b 100644
--- a/src/js/utils/filter-source.js
+++ b/src/js/utils/filter-source.js
@@ -32,19 +32,16 @@ const filterSource = function(src) {
       }
     });
 
-    src = newsrc;
-  } else if (typeof src === 'string' && src.trim()) {
+    return newsrc;
+  } if (typeof src === 'string' && src.trim()) {
     // convert string into object
-    src = [fixSource({src})];
-  } else if (isObject(src) && typeof src.src === 'string' && src.src && src.src.trim()) {
+    return [fixSource({src})];
+  } if (isObject(src) && typeof src.src === 'string' && src.src && src.src.trim()) {
     // src is already valid
-    src = [fixSource(src)];
-  } else {
-    // invalid source, turn it into an empty array
-    src = [];
+    return [fixSource(src)];
   }
-
-  return src;
+  // invalid source, turn it into an empty array
+  return [];
 };
 
 /**
diff --git a/src/js/utils/fn.js b/src/js/utils/fn.js
index cf7ba35ed4..df5ccc4760 100644
--- a/src/js/utils/fn.js
+++ b/src/js/utils/fn.js
@@ -60,19 +60,15 @@ export const bind_ = function(context, fn, uid) {
  *
  * @return   {Function}
  */
-export const throttle = function(fn, wait) {
-  let last = window.performance.now();
-
-  const throttled = function(...args) {
-    const now = window.performance.now();
-
-    if (now - last >= wait) {
-      fn(...args);
-      last = now;
-    }
+export const throttle = function(func, delay) {
+  let lastCallTime = 0;
+  return function throttled(...args) {
+      const currentTime = Date.now()
+      if (currentTime - lastCallTime >= delay) {
+          lastCallTime = currentTime;
+          func(...args);
+      }
   };
-
-  return throttled;
 };
 
 /**
diff --git a/src/js/utils/time.js b/src/js/utils/time.js
index 408bea08fb..b6f7c44477 100644
--- a/src/js/utils/time.js
+++ b/src/js/utils/time.js
@@ -141,7 +141,7 @@ function createTimeRangesObj(ranges) {
 export function createTimeRanges(start, end) {
   if (Array.isArray(start)) {
     return createTimeRangesObj(start);
-  } else if (start === undefined || end === undefined) {
+  } if (start === undefined || end === undefined) {
     return createTimeRangesObj();
   }
   return createTimeRangesObj([[start, end]]);