Informal code review to tidy up logger buffer fetching implementation

src/js/logger-ui.js

@@ -505,10 +505,7 @@ var truncateLog = function(size) {
 /******************************************************************************/
 
 const onLogBufferRead = function(response) {
-    if ( !response || response.unavailable ) {
-        readLogBufferAsync();
-        return;
-    }
+    if ( !response || response.unavailable ) { return; }
 
     // Disable tooltips?
     if (
@@ -565,23 +562,24 @@ const onLogBufferRead = function(response) {
         'disabled',
         tbody.querySelector('tr') === null
     );
-
-    readLogBufferAsync();
 };
 
 /******************************************************************************/
 
-// This can be called only once, at init time. After that, this will be called
-// automatically. If called after init time, this will be messy, and this would
-// require a bit more code to ensure no multi time out events.
+const readLogBuffer = (function() {
+    let timer;
 
-const readLogBuffer = function() {
+    const readLogBufferNow = function() {
         if ( logger.ownerId === undefined ) { return; }
+
         const msg = {
             what: 'readAll',
             ownerId: logger.ownerId,
             tabIdsToken: allTabIdsToken,
         };
+
+        // This is to detect changes in the position or size of the logger
+        // popup window (if in use).
         if (
             popupLoggerBox instanceof Object &&
             (
@@ -597,14 +595,25 @@ const readLogBuffer = function() {
             popupLoggerBox.h = self.outerHeight;
             msg.popupLoggerBoxChanged = true;
         }
-    vAPI.messaging.send('loggerUI', msg, onLogBufferRead);
+
+        vAPI.messaging.send('loggerUI', msg, response => {
+            timer = undefined;
+            onLogBufferRead(response);
+            readLogBufferLater();
+        });
     };
 
-const readLogBufferAsync = function() {
+    const readLogBufferLater = function() {
+        if ( timer !== undefined ) { return; }
         if ( logger.ownerId === undefined ) { return; }
-    vAPI.setTimeout(readLogBuffer, 1200);
+        timer = vAPI.setTimeout(readLogBufferNow, 1200);
     };
 
+    readLogBufferNow();
+
+    return readLogBufferLater;
+})();
+ 
 /******************************************************************************/
 
 let pageSelectorChanged = function() {
@@ -1802,7 +1811,7 @@ const grabView = function() {
     if ( logger.ownerId === undefined ) {
         logger.ownerId = Date.now();
     }
-    readLogBufferAsync();
+    readLogBuffer();
 };
 
 const releaseView = function() {
@@ -1821,8 +1830,6 @@ window.addEventListener('beforeunload', releaseView);
 
 /******************************************************************************/
 
-readLogBuffer();
-
 uDom('#pageSelector').on('change', pageSelectorChanged);
 uDom('#refresh').on('click', reloadTab);