enable to add an element with ordinal

with a safer way to assign ordinal, not relying on loop (which is based on
array length) but on existing ordinal, to better handle legacy element
without ordinal

server/controllers/listings/lib/elements.ts

@@ -1,4 +1,4 @@
-import { map } from 'lodash-es'
+import { map, maxBy } from 'lodash-es'
 import dbFactory from '#db/couchdb/base'
 import { isNonEmptyArray } from '#lib/boolean_validations'
 import { newError } from '#lib/error/error'
@@ -41,12 +41,12 @@ export async function createListingElements ({ listing, uris, userId }) {
   if (listing.creator !== userId) {
     throw newError('wrong user', 403, { userId, listingId })
   }
-  let currentOrdinal = 0
   const elements = uris.map(uri => {
+    const ordinal = highestOrdinal(listing.elements) + 1
     return createElementDoc({
       list: listingId,
       uri,
-      ordinal: currentOrdinal++,
+      ordinal,
     })
   })
   const res = await db.bulk(elements)
@@ -61,3 +61,10 @@ export async function bulkUpdateElements ({ oldElements, attribute, value }) {
 }
 
 const elementsBulkUpdate = db.bulk
+
+function highestOrdinal (elements: ListingElement[]) {
+  if (elements.length === 0) return -1
+
+  const highestOrdinalElement = maxBy(elements, 'ordinal')
+  return highestOrdinalElement.ordinal
+}

tests/api/listings/ordinal.test.ts

@@ -1,20 +1,9 @@
-import { createEdition } from '../fixtures/entities.js'
-import { createListing } from '../fixtures/listings.js'
-import { authReq } from '../utils/utils.js'
-
-const endpoint = '/api/lists?action='
-const byIds = `${endpoint}by-ids&with-elements=true`
+import { createListingWithElements } from '../fixtures/listings.js'
 
 describe('element:listing-ordinal', () => {
-  it('should add elements with ordinals', async () => {
-    const { listing } = await createListing()
-    const { uri } = await createEdition()
-    await authReq('post', `${endpoint}add-elements`, {
-      id: listing._id,
-      uris: [ uri ],
-    })
-    const res = await authReq('get', `${byIds}&ids=${listing._id}`)
-    const firstListing = res.lists[listing._id]
-    firstListing.elements[0].ordinal.should.equal(0)
+  it('should create elements with a listingId', async () => {
+    const { listing } = await createListingWithElements()
+    listing.elements[0].ordinal.should.equal(0)
+    listing.elements[1].ordinal.should.equal(1)
   })
 })