MAGETWO-52987: Checkout Zip Validation is not working with specific shipping settings

Author: Stanislav Idolov

app/code/Magento/Checkout/view/frontend/web/js/model/shipping-rates-validator.js

@@ -29,7 +29,8 @@ define(
         var checkoutConfig = window.checkoutConfig,
             validators = [],
             observedElements = [],
-            postcodeElement = null;
+            postcodeElement = null,
+            postcodeElementName = 'postcode';
 
         return {
             validateAddressTimeout: 0,
@@ -50,7 +51,7 @@ define(
              * @return {Boolean}
              */
             validateAddressData: function (address) {
-                return validators.some(function(validator) {
+                return validators.some(function (validator) {
                     return validator.validate(address);
                 });
             },
@@ -64,6 +65,12 @@ define(
                 var self = this,
                     elements = shippingRatesValidationRules.getObservableFields();
 
+                //TODO: Split zip code validation and element binding for shipping rates request
+                if ($.inArray(postcodeElementName, elements) === -1) {
+                    // Add postcode field to observables if not exist for zip code validation support
+                    elements.push(postcodeElementName);
+                }
+
                 $.each(elements, function (index, field) {
                     uiRegistry.async(formPath + '.' + field)(self.doElementBinding.bind(self));
                 });
@@ -80,12 +87,12 @@ define(
                 var observableFields = shippingRatesValidationRules.getObservableFields();
 
                 if (element && (observableFields.indexOf(element.index) !== -1 || force)) {
-                    if (element.index !== 'postcode') {
+                    if (element.index !== postcodeElementName) {
                         this.bindHandler(element, delay);
                     }
                 }
 
-                if (element.index === 'postcode') {
+                if (element.index === postcodeElementName) {
                     this.bindHandler(element, delay);
                     postcodeElement = element;
                 }