use email-newsletter layout data from frontend

dotcom-rendering/docs/email-newsletters-page.md

@@ -13,13 +13,8 @@ It is served using a dedicated route handler ([dotcom-rendering/src/server/handl
 
 ## Arranging the Newsletters
 
-The page model from frontend includes an array of the `Newsletters` that can be rendered on the page, but how those newsletters are sorted and grouped on the layout is determined by the `enhanceNewslettersPage` function.
+The page model from frontend includes an array of the `Newsletters` and an optional `layout` describing which of the `Newsletters` are rendered and how they are sorted and grouped on the page.
 
-In effect, to add a new newsletter to the page, or change the ordering, update the data in this file:
-dotcom-rendering/src/model/newsletter-grouping.ts
+The `layout`s send from frontend are defined in the [newsletters tool](https://newsletters-tool.gutools.co.uk/layouts).
 
-The file allows for alternative arrangements of newsletters based on the `EditionId`. The property used in the arrays of newsletters is the `Newsletter.identityName`.
-
-To find the correct position of the newsletter check this [spreadsheet](https://docs.google.com/spreadsheets/d/1Pfdow0Yj8OzkrnIWqIC-oSzVhwtwwDBdLmFx5hY-Gt4/edit#gid=2084088730)
-
-To find the `identityName` of a newsletter or whether it is launched or draft check the [newsletters tool](https://newsletters-tool.gutools.co.uk/)
+If no `layout` is provided by frontend, the `enhanceNewslettersPage` uses a default grouping to arrange the `Newsletters`.

dotcom-rendering/src/model/enhance-newsletters-page.ts

@@ -1,14 +1,12 @@
-import type { Newsletter } from '../types/content';
+import type { Newsletter, NewsletterLayout } from '../types/content';
 import type {
 	DCRNewslettersPageType,
 	FENewslettersPageType,
 	GroupedNewsletters,
 } from '../types/newslettersPage';
-import type { StaticGroups } from './newsletter-grouping';
-import { groups } from './newsletter-grouping';
 
-const mapStaticGroups = (
-	staticGroups: StaticGroups,
+const mapLayoutToGroups = (
+	layout: NewsletterLayout,
 	newsletters: Newsletter[],
 ): GroupedNewsletters => {
 	const newsletterRecord = newsletters.reduce<
@@ -18,7 +16,7 @@ const mapStaticGroups = (
 		return record;
 	}, {});
 
-	const mapped = staticGroups.map((group) => ({
+	const mapped = layout.groups.map((group) => ({
 		title: group.title,
 		subtitle: group.subtitle,
 		newsletters: group.newsletters.reduce<Newsletter[]>((list, name) => {
@@ -63,11 +61,10 @@ const reduceToDefaultGrouping = (
 const getGroups = (
 	newsletterPageData: FENewslettersPageType,
 ): GroupedNewsletters => {
-	const { newsletters, editionId } = newsletterPageData;
-	const staticGroup = groups[editionId] ?? groups['UK'];
+	const { newsletters, layout } = newsletterPageData;
 
-	return staticGroup
-		? mapStaticGroups(staticGroup, newsletters)
+	return layout
+		? mapLayoutToGroups(layout, newsletters)
 		: reduceToDefaultGrouping(newsletters);
 };