fix(customers): CUST-4064 Update state and zip optionality to be loaded via v1 country-states

[bc-akshatkaushik]

What?

Update state and zip optionality to be loaded via v1 country-states to dynamically load state and zip optionality based on the user's Country selection interation

Related PRs:

• https://github.com/bigcommerce/bigcommerce/pull/66139
• https://github.com/bigcommerce/storefront/pull/4342

Requirements

• CHANGELOG.md entry added (required for code changes only)

Tickets / Documentation

• CUST-4064

Screenshots (if appropriate)

Tested E2E with associated PRs linked above

Before

Screen.Recording.2025-12-23.at.12.38.00.pm.mov

After

Screen.Recording.2025-12-23.at.12.42.16.pm.mov

@bigcommerce/team-customers

[Copilot]

Pull request overview

This PR implements dynamic postal code (zip) validation based on country selection by integrating with the v1 country-states API. When a user selects a country in address or registration forms, the system now dynamically determines whether the postal code field is required based on the requiresPostalCodes property from the API response, similar to how state/province field requirements are handled.

Key Changes:

• Added dynamic postal code requirement logic to state-country module
• Integrated zip field validation handling in account and registration forms
• Default zip requirement behavior falls back to true when API doesn't specify

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
assets/js/theme/common/state-country.js	Added makeZipRequired/makeZipOptional helper functions and zip validation logic that reads requiresPostalCodes from country API response
assets/js/theme/auth.js	Added zip element selection and dynamic validation for registration form based on required attribute state
assets/js/theme/account.js	Added zip element selection and dynamic validation for address form based on required attribute state
package-lock.json	Version bump to 6.18.0-rc.1
CHANGELOG.md	Added entry for CUST-4064 dynamic postal code validation feature

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 5 changed files in this pull request and generated 4 comments.

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[bc-amandalan]

LGTM, thanks AK.

[bc-alexsaiannyi]

hey @bc-akshatkaushik, thanks for update! LGTM.

[bc-yevhenii-buliuk]

LGTM! Just don't forget squash all commits before merging the PR.