Add barcode encoded qty functionality to shelf inventory interface

shelfs/static/css/shelfs.css

@@ -150,7 +150,9 @@ div#container_edition {
 #product_uom {
   font-size: small;
 }
-
+#reset_to_previous_qty {
+  cursor: pointer;
+}
 .blink_me {
   animation: blinker 1s ease-in-out;
 }

shelfs/static/js/shelf_inventory.js

@@ -102,6 +102,12 @@ function barcode_analyzer(chars) {
         select_product_from_bc(barcode);
     }
 }
+
+function reset_previous_value() {
+    if (editing_item != null) {
+        $('#edition_input').val(editing_item.qty);
+    }
+}
 // Directly send a line to edition when barcode is read
 function select_product_from_bc(barcode) {
     var found = null,
@@ -837,7 +843,10 @@ function init() {
       */
         });
         if ($(this).val().length > 0) {
-            $("#reset_to_previous_qty").show();
+            let reset_icon = $("#reset_to_previous_qty");
+            reset_icon.show();
+            reset_icon.off();
+            reset_icon.on("click", reset_previous_value);
         } else {
             $("#reset_to_previous_qty").hide();
         }