Peer review.

`const` for constants, `let` for variables, line comment formatting,
max line length at 120.

app/assets/javascripts/qpixel_api.js

@@ -13,7 +13,7 @@ window.QPixel = {
   },
 
   /** Counts notifications popped up at any time. */
-  var popped_modals_ct = 0;
+  let popped_modals_ct = 0;
 
   /**
    * Create a notification popup - not an inbox notification.
@@ -21,30 +21,28 @@ window.QPixel = {
    * @param message the message to show
    */
   createNotification: function(type, message) {
-    /** Some messages include a date stamp. */
-    var append_date = false;
-    var message_with_date = message;
-    var span, button;
+    // Some messages include a date stamp, `append_date` governs that.
+    let append_date = false;
+    let message_with_date = message;
     if (type === 'danger') {
       if (popped_modals_ct > 0 ) {
-        /* Modals stack each on top, so repeating an errored action over
-         * and over again is gonna create multiple error modals in the
-         * same exact place. While this happens this way, an user
-         * closing the error modal will not have an immediate visual
-         * action feedback if two or more error modals are printed.
-         * A date is stamped in order to cope with that. */
+        /* At the time of writing, modals stack each one exactly on top of previous one, so repeating an errored action
+         * over and over again is going to create multiple error modals in the same exact place. While this happens this
+         * way, an user closing the error modal will not have an immediate visual action feedback if two or more error
+         * modals have been printed. A date is stamped in order to cope with that. Could be anything. Probablye a cycle
+         * of different emoji characters would be cuter while having the purpose met. But if so make sure character in
+         * step `i` is actually different than character in step `i + 1`. And then you could print an emoji just every
+         * time a modal is popped up, not just from the second one; removing `mesage_with_date`, using only `message`,
+         * and removing `append_date` and the different situations guarded by it. */
         append_date = true;
       }
     }
     if (append_date) {
       message_with_date += ' (' + new Date(Date.now()).toISOString() + ')';
     }
-    span = '<span aria-hidden="true">&times;</span>';
-    button = '<button';
-    button += ' type="button" class="button is-close-button"';
-    button += ' data-dismiss="alert" aria-label="Close"';
-    button += '>';
-    button += span + '</button>';
+    const span = '<span aria-hidden="true">&times;</span>';
+    const button = ('<button type="button" class="button is-close-button" data-dismiss="alert" aria-label="Close">' +
+        span + '</button>');
     $("<div></div>")
     .addClass("notice has-shadow-3 is-" + type)
     .html(button + '<p>' + message_with_date + '</p>')