Controlling Your Checkout Flow: Mastering useBuyerJourneyIntercept in Shopify

Decoding Shopify's useBuyerJourneyIntercept: A Community Deep Dive

Ever felt like you're wrestling with Shopify's checkout process when building custom UI extensions? You're not alone! Recently, a fellow developer, KedarMalap, sparked a great conversation in the Shopify Community about the useBuyerJourneyIntercept hook and how it behaves, especially with the single-page checkout. Let's unpack what they discovered and how you can avoid similar headaches.

The Initial Question: When Does it Actually Run?

KedarMalap was building a checkout UI extension that requires customers to accept terms and conditions before completing their order. Makes sense, right? They used useBuyerJourneyIntercept to block progress if the terms checkbox wasn't checked. The problem? On the single-page checkout, the interceptor was firing not just when the buyer clicked "Pay now," but also when they were editing their address or other fields. This led to some confusing validation messages popping up prematurely.

Here's how KedarMalap framed the core question:

On single-page checkout, the interceptor seems to run not only when the buyer clicks “Pay now”, but also when they edit other fields (e.g. address). That causes the terms validation to show while they’re still filling the form, which is confusing.

They wanted to know if the interceptor was only supposed to run on final submission or if it was also triggered by other progress events like address validation or field blur. Good question!

The Answer: It's More Frequent Than You Think

Anmolkumar jumped in to clarify that useBuyerJourneyIntercept runs whenever Shopify evaluates checkout progress. That's not just on "Pay now" clicks. It includes address updates, step changes, and even internal re-validations, especially on the single-page checkout. The key takeaway? There's no "final submit only" trigger.

Anmolkumar's response:

useBuyerJourneyIntercept runs whenever Shopify evaluates checkout progress not just on “Pay now.That includes step changes, address updates, and internal re-validations especially on single-page checkout.There’s no final submit only trigger. The correct approach is to check buyerJourney.activeStep and only return block on the paymentfinal step.

The Challenge with Single-Page Checkout

As KedarMalap pointed out, on a single-page checkout, buyerJourney.activeStep is often just 'checkout'. This means if you naively block progress when activeStep === 'checkout', you'll be blocking on every evaluation, including address updates. Not ideal!

A Potential Workaround: Fine-Grained Control

So, what's the solution? The suggested approach is to accept that the interceptor will run on all progress events, but to only block when activeStep === 'checkout' and your specific conditions aren't met (e.g., terms aren't accepted). This means you'll need to live with the fact that the validation might run during address changes, but you can minimize the impact by only showing the error message when it truly matters – right before payment.

KedarMalap's initial workaround:

I’m using buyerJourney.activeStep and only blocking when the current step is payment or checkout, which improves multi-step checkout but doesn’t fully fix single-page checkout if the interceptor runs on every progress/validation event.

Key Takeaways and Considerations

• useBuyerJourneyIntercept is triggered frequently, not just on final submission.
• Single-page checkouts present a unique challenge because buyerJourney.activeStep might always be 'checkout'.
• You'll likely need to accept that the interceptor runs on all progress events and implement logic to only block when necessary.

Relevant API References (from the original post)

• useBuyerJourneyIntercept (React) / buyerJourney.intercept() (Preact/vanilla)
• Extension target: purchase.checkout.actions.render-before
• Capability: block_progress

Here's a reminder of the context of the issue:

Ultimately, mastering useBuyerJourneyIntercept requires a bit of finesse and understanding of how Shopify evaluates checkout progress. By carefully considering the activeStep and your specific validation logic, you can create a smoother, less confusing experience for your customers. It's all about understanding the nuances of the platform and adapting your approach accordingly. Happy coding!