I am editing this file

RootFolder\vendor\magento\module-checkout\view\frontend\layout\checkout_index_index

to add new validations to the checkout.

For fields like "telephone" I just need to edit it like this:

<item name="telephone" xsi:type="array"> 
<item name="config" xsi:type="array"> 
<item name="tooltip" xsi:type="array"> 
<item name="description" xsi:type="string" translate="true">For delivery questions.</item> </item> </item> 

<!-- Validation starts --> 
<item name="validation" xsi:type="array"> 
<item name="validate-email" xsi:type="boolean">true</item> </item>
 <!-- Validation ends -->
 </item>

But I can't find where to add a validation to one of the address fields

Does somebody how to add a validation to one of the address fields?

I am editing this file

RootFolder\vendor\magento\module-checkout\view\frontend\layout\checkout_index_index

To add new validations to the checkout.

For fields like telephone I just need to edit it like this:

<item name="telephone" xsi:type="array"> 
<item name="config" xsi:type="array"> 
<item name="tooltip" xsi:type="array"> 
<item name="description" xsi:type="string" translate="true">For delivery questions.</item> </item> </item> 

<!-- Validation starts --> 
<item name="validation" xsi:type="array"> 
<item name="validate-email" xsi:type="boolean">true</item> </item>
 <!-- Validation ends -->
 </item>

But I can't find where to add a validation to one of the address fields

Does somebody know how to add a validation to one of the address fields?