fix(headless): update product interface to reflect how the commerce api behaves

[olamothe]

This is less changes that what I had originally thought.

The BaseProduct interface should now properly reflect what's returned by the commerce API, following the source of truth (the code of the service itself).

• Most of the change are about changing from foo | undefined to foo | null.
• Array values are never null, but might be an empty array (due to how the service is coded)
• ec_category is always an array, not a string
• Added couple missing properties (non breaking)

There is only "one lie" in this change: excerpts, nameHighlights, excerptsHighlights are "always defined when in a search use case", and "always undefined when in a listing or recommendation use case".

I thought about splitting and creating multiple interface SearchProduct, ListingProduct, RecommendationProduct, and remove Product as it exists right now.

However this would be a very noisy change, for existing deployments. Product is an important interface, which is nearly always referenced by any implementer using TypeScript.

So I made the judgment call to "lie a little bit, for the greater good" 😂 They are marked as possibly undefined for all use cases.

https://coveord.atlassian.net/browse/KIT-3164

[developer-experience-bot]

Pull Request Report

PR Title

✅ Title follows the conventional commit spec.

Live demo links

• Storybook

• Playwright report

Bundle Size

File	Old (kb)	New (kb)	Change (%)
case-assist	204.9	204.9	0
commerce	293.1	293.1	0
search	372.4	372.4	0
insight	352.4	352.4	0
product-listing	267	267	0
product-recommendation	170.8	170.8	0
recommendation	217.8	217.8	0
ssr	365.2	365.2	0

SSR Progress

Use case	SSR (#)	CSR (#)	Progress (%)
search	39	44	89
recommendation	0	4	0
product-recommendation	0	10	0
product-listing	0	13	0
case-assist	0	6	0
insight	0	27	0
commerce	0	15	0

Detailed logs

search : buildInteractiveResult
search : buildInteractiveInstantResult
search : buildInteractiveRecentResult
search : buildInteractiveCitation
search : buildGeneratedAnswer
recommendation : missing SSR support
product-recommendation : missing SSR support
product-listing : missing SSR support
case-assist : missing SSR support
insight : missing SSR support
commerce : missing SSR support

[buggyvelarde]

Nice types!