[frontend]: fix global scope, change var to let

7 files changed, 87 insertions, 84 deletions

diff --git a/youtube/static/js/av-merge.js b/youtube/static/js/av-merge.js
index bbe3e35..e7d5c25 100644
--- a/youtube/static/js/av-merge.js
+++ b/youtube/static/js/av-merge.js
@@ -41,7 +41,7 @@ function AVMerge(video, srcInfo, startTime){
     }
 
     // Find supported video and audio sources
-    for (var src of srcInfo['videos']) {
+    for (let src of srcInfo['videos']) {
         if (MediaSource.isTypeSupported(src['mime_codec'])) {
             reportDebug('Using video source', src['mime_codec'],
                         src['quality_string'], 'itag', src['itag']);
@@ -49,7 +49,7 @@ function AVMerge(video, srcInfo, startTime){
             break;
         }
     }
-    for (var src of srcInfo['audios']) {
+    for (let src of srcInfo['audios']) {
         if (MediaSource.isTypeSupported(src['mime_codec'])) {
             reportDebug('Using audio source', src['mime_codec'],
                         src['quality_string'], 'itag', src['itag']);
@@ -205,9 +205,9 @@ Stream.prototype.setup = async function(){
             this.initRange.start,
             this.indexRange.end,
             (buffer) => {
-                var init_end = this.initRange.end - this.initRange.start + 1;
-                var index_start = this.indexRange.start - this.initRange.start;
-                var index_end = this.indexRange.end - this.initRange.start + 1;
+                let init_end = this.initRange.end - this.initRange.start + 1;
+                let index_start = this.indexRange.start - this.initRange.start;
+                let index_end = this.indexRange.end - this.initRange.start + 1;
                 this.setupInitSegment(buffer.slice(0, init_end));
                 this.setupSegmentIndex(buffer.slice(index_start, index_end));
             }
@@ -247,7 +247,7 @@ Stream.prototype.setupSegmentIndex = async function(indexSegment){
                 entry.referencedSize = entry.end - entry.start + 1;
         }
     } else {
-        var box = unbox(indexSegment);
+        let box = unbox(indexSegment);
         this.sidx = sidx_parse(box.data, this.indexRange.end+1);
     }
     this.fetchSegmentIfNeeded(this.getSegmentIdx(this.startTime));
@@ -289,8 +289,8 @@ Stream.prototype.appendSegment = function(segmentIdx, chunk) {
 
         // Count how many bytes are in buffer to update buffering target,
         // updating .have as well for when we need to delete segments
-        var bytesInBuffer = 0;
-        for (var i = 0; i < this.sidx.entries.length; i++) {
+        let bytesInBuffer = 0;
+        for (let i = 0; i < this.sidx.entries.length; i++) {
             if (this.segmentInBuffer(i))
                 bytesInBuffer += this.sidx.entries[i].referencedSize;
             else if (this.sidx.entries[i].have) {
@@ -306,11 +306,11 @@ Stream.prototype.appendSegment = function(segmentIdx, chunk) {
 
         // Delete 10 segments (arbitrary) from buffer, making sure
         // not to delete current one
-        var currentSegment = this.getSegmentIdx(this.video.currentTime);
-        var numDeleted = 0;
-        var i = 0;
+        let currentSegment = this.getSegmentIdx(this.video.currentTime);
+        let numDeleted = 0;
+        let i = 0;
         const DELETION_TARGET = 10;
-        var toDelete = []; // See below for why we have to schedule it
+        let toDelete = []; // See below for why we have to schedule it
         this.reportDebug('Deleting segments from beginning of buffer.');
         while (numDeleted < DELETION_TARGET && i < currentSegment) {
             if (this.sidx.entries[i].have) {
@@ -334,9 +334,9 @@ Stream.prototype.appendSegment = function(segmentIdx, chunk) {
         // When calling .remove, the sourceBuffer will go into updating=true
         // state, and remove cannot be called until it is done. So we have
         // to delete on the updateend event for subsequent ones.
-        var removeFinishedEvent;
-        var deletedStuff = (toDelete.length !== 0)
-        var deleteSegment = () => {
+        let removeFinishedEvent;
+        let deletedStuff = (toDelete.length !== 0)
+        let deleteSegment = () => {
             if (toDelete.length === 0) {
                 removeFinishedEvent.remove();
                 // If QuotaExceeded happened for current segment, retry the
@@ -370,19 +370,19 @@ Stream.prototype.appendSegment = function(segmentIdx, chunk) {
 }
 Stream.prototype.getSegmentIdx = function(videoTime) {
     // get an estimate
-    var currentTick = videoTime * this.sidx.timeScale;
-    var firstSegmentDuration = this.sidx.entries[0].subSegmentDuration;
-    var index = 1 + Math.floor(currentTick / firstSegmentDuration);
-    var index = clamp(index, 0, this.sidx.entries.length - 1);
+    let currentTick = videoTime * this.sidx.timeScale;
+    let firstSegmentDuration = this.sidx.entries[0].subSegmentDuration;
+    let index = 1 + Math.floor(currentTick / firstSegmentDuration);
+    index = clamp(index, 0, this.sidx.entries.length - 1);
 
-    var increment = 1;
+    let increment = 1;
     if (currentTick < this.sidx.entries[index].tickStart){
         increment = -1;
     }
 
     // go up or down to find correct index
     while (index >= 0 && index < this.sidx.entries.length) {
-        var entry = this.sidx.entries[index];
+        let entry = this.sidx.entries[index];
         if (entry.tickStart <= currentTick && (entry.tickEnd+1) > currentTick){
             return index;
         }
@@ -396,11 +396,11 @@ Stream.prototype.checkBuffer = async function() {
         return;
     }
     // Find the first unbuffered segment, i
-    var currentSegmentIdx = this.getSegmentIdx(this.video.currentTime);
-    var bufferedBytesAhead = 0;
-    var i;
+    let currentSegmentIdx = this.getSegmentIdx(this.video.currentTime);
+    let bufferedBytesAhead = 0;
+    let i;
     for (i = currentSegmentIdx; i < this.sidx.entries.length; i++) {
-        var entry = this.sidx.entries[i];
+        let entry = this.sidx.entries[i];
         // check if we had it before, but it was deleted by the browser
         if (entry.have && !this.segmentInBuffer(i)) {
             this.reportDebug('segment', i, 'deleted by browser');
@@ -428,9 +428,9 @@ Stream.prototype.checkBuffer = async function() {
     }
 }
 Stream.prototype.segmentInBuffer = function(segmentIdx) {
-    var entry = this.sidx.entries[segmentIdx];
+    let entry = this.sidx.entries[segmentIdx];
     // allow for 0.01 second error
-    var timeStart = entry.tickStart/this.sidx.timeScale + 0.01;
+    let timeStart = entry.tickStart/this.sidx.timeScale + 0.01;
 
     /* Some of YouTube's mp4 fragments are malformed, with half-frame
     playback gaps. In this video at 240p (timeScale = 90000 ticks/second)
@@ -457,14 +457,15 @@ Stream.prototype.segmentInBuffer = function(segmentIdx) {
     quality switching, YouTube likely encodes their formats to line up nicely.
     Either there is a bug in their encoder, or this is intentional. Allow for
     up to 1 frame-time of error to work around this issue. */
+    let endError;
     if (this.streamType == 'video')
-        var endError = 1/(this.avMerge.videoSource.fps || 30);
+        endError = 1/(this.avMerge.videoSource.fps || 30);
     else
-        var endError = 0.01
-    var timeEnd = (entry.tickEnd+1)/this.sidx.timeScale - endError;
+        endError = 0.01
+    let timeEnd = (entry.tickEnd+1)/this.sidx.timeScale - endError;
 
-    var timeRanges = this.sourceBuffer.buffered;
-    for (var i=0; i < timeRanges.length; i++) {
+    let timeRanges = this.sourceBuffer.buffered;
+    for (let i=0; i < timeRanges.length; i++) {
         if (timeRanges.start(i) <= timeStart && timeEnd <= timeRanges.end(i)) {
             return true;
         }
@@ -505,7 +506,7 @@ Stream.prototype.fetchSegmentIfNeeded = function(segmentIdx) {
     this.fetchSegment(segmentIdx);
 }
 Stream.prototype.handleSeek = function() {
-    var segmentIdx = this.getSegmentIdx(this.video.currentTime);
+    let segmentIdx = this.getSegmentIdx(this.video.currentTime);
     this.fetchSegmentIfNeeded(segmentIdx);
 }
 Stream.prototype.reportDebug = function(...args) {
@@ -523,7 +524,7 @@ Stream.prototype.reportError = function(...args) {
 
 function fetchRange(url, start, end, cb) {
     return new Promise((resolve, reject) => {
-        var xhr = new XMLHttpRequest();
+        let xhr = new XMLHttpRequest();
         xhr.open('get', url);
         xhr.responseType = 'arraybuffer';
         xhr.setRequestHeader('Range', 'bytes=' + start + '-' + end);
@@ -536,15 +537,15 @@ function fetchRange(url, start, end, cb) {
 }
 
 function debounce(func, wait, immediate) {
-    var timeout;
+    let timeout;
     return function() {
-        var context = this;
-        var args = arguments;
-        var later = function() {
+        let context = this;
+        let args = arguments;
+        let later = function() {
             timeout = null;
             if (!immediate) func.apply(context, args);
         };
-        var callNow = immediate && !timeout;
+        let callNow = immediate && !timeout;
         clearTimeout(timeout);
         timeout = setTimeout(later, wait);
         if (callNow) func.apply(context, args);
@@ -580,7 +581,7 @@ function reportDebug(...args){
 }
 
 function byteArrayToIntegerLittleEndian(unsignedByteArray){
-    var result = 0;
+    let result = 0;
     for (byte of unsignedByteArray){
         result = result*256;
         result += byte
@@ -588,7 +589,7 @@ function byteArrayToIntegerLittleEndian(unsignedByteArray){
     return result;
 }
 function byteArrayToFloat(byteArray) {
-    var view = new DataView(byteArray.buffer);
+    let view = new DataView(byteArray.buffer);
     if (byteArray.length == 4)
         return view.getFloat32(byteArray.byteOffset);
     else
@@ -599,14 +600,14 @@ function ByteParser(data){
     this.data = new Uint8Array(data);
 }
 ByteParser.prototype.readInteger = function(nBytes){
-    var result = byteArrayToIntegerLittleEndian(
+    let result = byteArrayToIntegerLittleEndian(
         this.data.slice(this.curIndex, this.curIndex + nBytes)
     );
     this.curIndex += nBytes;
     return result;
 }
 ByteParser.prototype.readBufferBytes = function(nBytes){
-    var result = this.data.slice(this.curIndex, this.curIndex + nBytes);
+    let result = this.data.slice(this.curIndex, this.curIndex + nBytes);
     this.curIndex += nBytes;
     return result;
 }
@@ -635,7 +636,7 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.*/
 function sidx_parse (data, offset) {
-	var bp = new ByteParser(data),
+	let bp = new ByteParser(data),
 		version = bp.readInteger(1),
 		flags = bp.readInteger(3),
 		referenceId = bp.readInteger(4),
@@ -646,9 +647,9 @@ function sidx_parse (data, offset) {
 		entryCount = bp.readInteger(2),
 		entries = [];
 
-    var totalBytesOffset = firstOffset + offset;
-    var totalTicks = 0;
-	for (var i = entryCount; i > 0; i=i-1 ) {
+    let totalBytesOffset = firstOffset + offset;
+    let totalTicks = 0;
+	for (let i = entryCount; i > 0; i=i-1 ) {
         let referencedSize = bp.readInteger(4),
 			subSegmentDuration = bp.readInteger(4),
 			unused = bp.readBufferBytes(4)
@@ -681,7 +682,7 @@ function sidx_parse (data, offset) {
 
 // BEGIN iso-bmff-parser-stream/lib/unbox.js (same license), modified
 function unbox(buf) {
-	var bp = new ByteParser(buf),
+	let bp = new ByteParser(buf),
 		bufferLength = buf.length,
 		length,
 		typeData,
@@ -712,7 +713,7 @@ function unbox(buf) {
 
 
 function extractWebmInitializationInfo(initializationSegment) {
-    var result = {
+    let result = {
         timeScale: null,
         cuesOffset: null,
         duration: null,
@@ -740,9 +741,9 @@ function extractWebmInitializationInfo(initializationSegment) {
     return result;
 }
 function parseWebmCues(indexSegment, initInfo) {
-    var entries = [];
-    var currentEntry = {};
-    var cuesOffset = initInfo.cuesOffset;
+    let entries = [];
+    let currentEntry = {};
+    let cuesOffset = initInfo.cuesOffset;
     (new EbmlDecoder()).readTags(indexSegment, (tagType, tag) => {
         if (tag.name == 'CueTime') {
             const tickStart = byteArrayToIntegerLittleEndian(tag.data);
@@ -818,7 +819,7 @@ EbmlDecoder.prototype.readTags = function(chunk, onParsedTag) {
 }
 EbmlDecoder.prototype.getSchemaInfo = function(tag) {
     if (Number.isInteger(tag) && schema.has(tag)) {
-        var name, type;
+        let name, type;
         [name, type] = schema.get(tag);
         return {name, type};
     }
diff --git a/youtube/static/js/comments.js b/youtube/static/js/comments.js
index fdd089f..14ba0c0 100644
--- a/youtube/static/js/comments.js
+++ b/youtube/static/js/comments.js
@@ -1,9 +1,9 @@
 function onClickReplies(e) {
-  var details = e.target.parentElement;
+  let details = e.target.parentElement;
   // e.preventDefault();
   console.log("loading replies ..");
   doXhr(details.getAttribute("data-src") + "&slim=1", (html) => {
-    var div = details.querySelector(".comment_page");
+    let div = details.querySelector(".comment_page");
     div.innerHTML = html;
   });
   details.removeEventListener('click', onClickReplies);
diff --git a/youtube/static/js/common.js b/youtube/static/js/common.js
index c15921c..79f8834 100644
--- a/youtube/static/js/common.js
+++ b/youtube/static/js/common.js
@@ -1,16 +1,19 @@
 const Q = document.querySelector.bind(document);
 const QA = document.querySelectorAll.bind(document);
 const QId = document.getElementById.bind(document);
+let seconds,
+    minutes,
+    hours;
 function text(msg) { return document.createTextNode(msg); }
 function clearNode(node) { while (node.firstChild) node.removeChild(node.firstChild); }
 function toTimestamp(seconds) {
-  var seconds = Math.floor(seconds);
+  seconds = Math.floor(seconds);
 
-  var minutes = Math.floor(seconds/60);
-  var seconds = seconds % 60;
+  minutes = Math.floor(seconds/60);
+  seconds = seconds % 60;
 
-  var hours = Math.floor(minutes/60);
-  var minutes = minutes % 60;
+  hours = Math.floor(minutes/60);
+  minutes = minutes % 60;
 
   if (hours) {
     return `0${hours}:`.slice(-3) + `0${minutes}:`.slice(-3) + `0${seconds}`.slice(-2);
@@ -18,8 +21,7 @@ function toTimestamp(seconds) {
   return `0${minutes}:`.slice(-3) + `0${seconds}`.slice(-2);
 }
 
-
-var cur_track_idx = 0;
+let cur_track_idx = 0;
 function getActiveTranscriptTrackIdx() {
     let textTracks = QId("js-video-player").textTracks;
     if (!textTracks.length) return;
@@ -39,7 +41,7 @@ function getDefaultTranscriptTrackIdx() {
 }
 
 function doXhr(url, callback=null) {
-    var xhr = new XMLHttpRequest();
+    let xhr = new XMLHttpRequest();
     xhr.open("GET", url);
     xhr.onload = (e) => {
       callback(e.currentTarget.response);
@@ -50,7 +52,7 @@ function doXhr(url, callback=null) {
 
 // https://stackoverflow.com/a/30810322
 function copyTextToClipboard(text) {
-  var textArea = document.createElement("textarea");
+  let textArea = document.createElement("textarea");
 
   //
   // *** This styling is an extra step which is likely not required. ***
@@ -97,8 +99,8 @@ function copyTextToClipboard(text) {
   textArea.select();
 
   try {
-    var successful = document.execCommand('copy');
-    var msg = successful ? 'successful' : 'unsuccessful';
+    let successful = document.execCommand('copy');
+    let msg = successful ? 'successful' : 'unsuccessful';
     console.log('Copying text command was ' + msg);
   } catch (err) {
     console.log('Oops, unable to copy');
diff --git a/youtube/static/js/playlistadd.js b/youtube/static/js/playlistadd.js
index 0a2a027..4b76ce1 100644
--- a/youtube/static/js/playlistadd.js
+++ b/youtube/static/js/playlistadd.js
@@ -37,7 +37,7 @@
     }
     // https://developer.mozilla.org/en-US/docs/Learn/HTML/Forms/Sending_forms_through_JavaScript
     function sendData(event){
-        var clicked_button = document.activeElement;
+        let clicked_button = document.activeElement;
         if(clicked_button === null || clicked_button.getAttribute('type') !== 'submit' || clicked_button.parentElement != event.target){
             console.log('ERROR: clicked_button not valid');
             return;
@@ -46,8 +46,8 @@
             return;     // video(s) are being removed from playlist, just let it refresh the page
         }
         event.preventDefault();
-        var XHR = new XMLHttpRequest();
-        var FD = new FormData(playlistAddForm);
+        let XHR = new XMLHttpRequest();
+        let FD = new FormData(playlistAddForm);
 
         if(FD.getAll('video_info_list').length === 0){
             displayMessage('Error: No videos selected', true);
diff --git a/youtube/static/js/plyr-start.js b/youtube/static/js/plyr-start.js
index 763a492..86840e9 100644
--- a/youtube/static/js/plyr-start.js
+++ b/youtube/static/js/plyr-start.js
@@ -16,10 +16,10 @@
 
   let qualityOptions = [];
   let qualityDefault;
-  for (var src of data['uni_sources']) {
+  for (let src of data['uni_sources']) {
     qualityOptions.push(src.quality_string)
   }
-  for (var src of data['pair_sources']) {
+  for (let src of data['pair_sources']) {
     qualityOptions.push(src.quality_string)
   }
   if (data['using_pair_sources'])
@@ -100,14 +100,14 @@
       onChange: function(quality) {
         if (quality == 'None') {return;}
         if (quality.includes('(integrated)')) {
-          for (var i=0; i < data['uni_sources'].length; i++) {
+          for (let i=0; i < data['uni_sources'].length; i++) {
             if (data['uni_sources'][i].quality_string == quality) {
               changeQuality({'type': 'uni', 'index': i});
               return;
             }
           }
         } else {
-          for (var i=0; i < data['pair_sources'].length; i++) {
+          for (let i=0; i < data['pair_sources'].length; i++) {
             if (data['pair_sources'][i].quality_string == quality) {
               changeQuality({'type': 'pair', 'index': i});
               return;
diff --git a/youtube/static/js/sponsorblock.js b/youtube/static/js/sponsorblock.js
index a2fd094..a929fc5 100644
--- a/youtube/static/js/sponsorblock.js
+++ b/youtube/static/js/sponsorblock.js
@@ -2,7 +2,7 @@
 
 // from: https://git.gir.st/subscriptionfeed.git/blob/59a590d:/app/youtube/templates/watch.html.j2#l28
 
-var sha256=function a(b){function c(a,b){return a>>>b|a<<32-b}for(var d,e,f=Math.pow,g=f(2,32),h="length",i="",j=[],k=8*b[h],l=a.h=a.h||[],m=a.k=a.k||[],n=m[h],o={},p=2;64>n;p++)if(!o[p]){for(d=0;313>d;d+=p)o[d]=p;l[n]=f(p,.5)*g|0,m[n++]=f(p,1/3)*g|0}for(b+="\x80";b[h]%64-56;)b+="\x00";for(d=0;d<b[h];d++){if(e=b.charCodeAt(d),e>>8)return;j[d>>2]|=e<<(3-d)%4*8}for(j[j[h]]=k/g|0,j[j[h]]=k,e=0;e<j[h];){var q=j.slice(e,e+=16),r=l;for(l=l.slice(0,8),d=0;64>d;d++){var s=q[d-15],t=q[d-2],u=l[0],v=l[4],w=l[7]+(c(v,6)^c(v,11)^c(v,25))+(v&l[5]^~v&l[6])+m[d]+(q[d]=16>d?q[d]:q[d-16]+(c(s,7)^c(s,18)^s>>>3)+q[d-7]+(c(t,17)^c(t,19)^t>>>10)|0),x=(c(u,2)^c(u,13)^c(u,22))+(u&l[1]^u&l[2]^l[1]&l[2]);l=[w+x|0].concat(l),l[4]=l[4]+w|0}for(d=0;8>d;d++)l[d]=l[d]+r[d]|0}for(d=0;8>d;d++)for(e=3;e+1;e--){var y=l[d]>>8*e&255;i+=(16>y?0:"")+y.toString(16)}return i}; /*https://geraintluff.github.io/sha256/sha256.min.js (public domain)*/
+let sha256=function a(b){function c(a,b){return a>>>b|a<<32-b}for(var d,e,f=Math.pow,g=f(2,32),h="length",i="",j=[],k=8*b[h],l=a.h=a.h||[],m=a.k=a.k||[],n=m[h],o={},p=2;64>n;p++)if(!o[p]){for(d=0;313>d;d+=p)o[d]=p;l[n]=f(p,.5)*g|0,m[n++]=f(p,1/3)*g|0}for(b+="\x80";b[h]%64-56;)b+="\x00";for(d=0;d<b[h];d++){if(e=b.charCodeAt(d),e>>8)return;j[d>>2]|=e<<(3-d)%4*8}for(j[j[h]]=k/g|0,j[j[h]]=k,e=0;e<j[h];){var q=j.slice(e,e+=16),r=l;for(l=l.slice(0,8),d=0;64>d;d++){var s=q[d-15],t=q[d-2],u=l[0],v=l[4],w=l[7]+(c(v,6)^c(v,11)^c(v,25))+(v&l[5]^~v&l[6])+m[d]+(q[d]=16>d?q[d]:q[d-16]+(c(s,7)^c(s,18)^s>>>3)+q[d-7]+(c(t,17)^c(t,19)^t>>>10)|0),x=(c(u,2)^c(u,13)^c(u,22))+(u&l[1]^u&l[2]^l[1]&l[2]);l=[w+x|0].concat(l),l[4]=l[4]+w|0}for(d=0;8>d;d++)l[d]=l[d]+r[d]|0}for(d=0;8>d;d++)for(e=3;e+1;e--){var y=l[d]>>8*e&255;i+=(16>y?0:"")+y.toString(16)}return i}; /*https://geraintluff.github.io/sha256/sha256.min.js (public domain)*/
 
 window.addEventListener("load", load_sponsorblock);
 document.addEventListener('DOMContentLoaded', ()=>{
diff --git a/youtube/static/js/watch.js b/youtube/static/js/watch.js
index acc6b28..95d9fa7 100644
--- a/youtube/static/js/watch.js
+++ b/youtube/static/js/watch.js
@@ -1,10 +1,10 @@
 const video = document.getElementById('js-video-player');
 
 function changeQuality(selection) {
-    var currentVideoTime = video.currentTime;
-    var videoPaused = video.paused;
-    var videoSpeed = video.playbackRate;
-    var srcInfo;
+    let currentVideoTime = video.currentTime;
+    let videoPaused = video.paused;
+    let videoSpeed = video.playbackRate;
+    let srcInfo;
     if (avMerge)
         avMerge.close();
     if (selection.type == 'uni'){
@@ -22,9 +22,9 @@ function changeQuality(selection) {
 }
 
 // Initialize av-merge
-var avMerge;
+let avMerge;
 if (data.using_pair_sources) {
-    var srcPair = data['pair_sources'][data['pair_idx']];
+    let srcPair = data['pair_sources'][data['pair_idx']];
     // Do it dynamically rather than as the default in jinja
     // in case javascript is disabled
     avMerge = new AVMerge(video, srcPair, 0);
@@ -42,10 +42,10 @@ if (qs) {
 if (data.time_start != 0 && video) {video.currentTime = data.time_start};
 
 // External video speed control
-var speedInput = document.getElementById('speed-control');
+let speedInput = document.getElementById('speed-control');
 speedInput.addEventListener('keyup', (event) => {
     if (event.key === 'Enter') {
-        var speed = parseFloat(speedInput.value);
+        let speed = parseFloat(speedInput.value);
         if(!isNaN(speed)){
             video.playbackRate = speed;
         }
@@ -61,7 +61,7 @@ if (data.playlist && data.playlist['id'] !== null) {
     // IntersectionObserver isn't supported in pre-quantum
     // firefox versions, but the alternative of making it
     // manually is a performance drain, so oh well
-    var observer = new IntersectionObserver(lazyLoad, {
+    let observer = new IntersectionObserver(lazyLoad, {
 
       // where in relation to the edge of the viewport, we are observing
       rootMargin: "100px",
@@ -86,7 +86,7 @@ if (data.playlist && data.playlist['id'] !== null) {
     };
 
     // Tell our observer to observe all img elements with a "lazy" class
-    var lazyImages = document.querySelectorAll('img.lazy');
+    let lazyImages = document.querySelectorAll('img.lazy');
     lazyImages.forEach(img => {
       observer.observe(img);
     });