[Administration] Documents : erreur JS pricesArray

backend/web/js/vuejs/document-form.js

             var pricesArray = product.prices;
             var unitCoefficient = product.unit_coefficient;
 
-            if (theQuantity) {
-                theQuantity = theQuantity / unitCoefficient;
-            }
+            if(pricesArray && unitCoefficient) {
+                if (theQuantity) {
+                    theQuantity = theQuantity / unitCoefficient;
+                }
 
-            for (var i = 0; i < pricesArray.length; i++) {
-                if(pricesArray[i]) {
-                    var price = pricesArray[i].price;
-                    var fromQuantity = pricesArray[i].from_quantity;
+                for (var i = 0; i < pricesArray.length; i++) {
+                    if(pricesArray[i]) {
+                        var price = pricesArray[i].price;
+                        var fromQuantity = pricesArray[i].from_quantity;
 
-                    if (price < thePrice && fromQuantity <= theQuantity) {
-                        thePrice = price;
+                        if (price < thePrice && fromQuantity <= theQuantity) {
+                            thePrice = price;
+                        }
                     }
                 }
             }