How can add custom validation in zip code field at checkout Magento2

Question

I have tried with all solution. Actually, i want to add number validationmeans anyone will not able to write characters in text-field.

when I see in the browser by inspect element then getting this code.

<input class="input-text" type="text" data-bind="
value: value,
valueUpdate: 'keyup',
hasFocus: focused,
attr: {
    name: inputName,
    placeholder: placeholder,
    'aria-describedby': noticeId,
    id: uid,
    disabled: disabled
}" name="postcode" placeholder="" aria-describedby="notice-HGXM9L3" id="HGXM9L3">

if we can also add any custom class then we can set validation by jquery. anyone have an idea for that, please.

Answer 1

Here I am sharing code for add custom validation to postcode field

checkout_index_index.xml file code for postcode field.

<item name="postcode" xsi:type="array">
    <!-- post-code field has custom UI component -->
    <item name="component" xsi:type="string">Magento_Ui/js/form/element/post-code</item>
    <item name="validation" xsi:type="array">
        <item name="required-entry" xsi:type="boolean">true</item>
    </item>
</item>

You need to add below code for number validation

<item name="validate-digits" xsi:type="string">true</item>

Final postcode field code

<item name="postcode" xsi:type="array">
    <!-- post-code field has custom UI component -->
    <item name="component" xsi:type="string">Magento_Ui/js/form/element/post-code</item>
    <item name="validation" xsi:type="array">
        <item name="required-entry" xsi:type="boolean">true</item>
        <item name="validate-digits" xsi:type="string">true</item>
    </item>
</item>

Note: You have to override checkout_index_index.xml in your theme.

Answer 2

Default magento 2 doesn't provide validation like anyone will not able to write characters in text-field. So you should go with custom jquery or HTML 5.

Please check below URL: https://stackoverflow.com/questions/995183/how-to-allow-only-numeric-0-9-in-html-inputbox-using-jquery

Hope above solution work for you.