Use first id characters in result filenames

src/history/delta/formats/id.js

@@ -1,4 +1,4 @@
-import { isValidId } from '../../merge/id.js'
+import { isValidId, stripUuidDashes } from '../../merge/id.js'
 
 // Deltas can be the `rawResult.id`
 const parseId = function (delta) {
@@ -11,8 +11,9 @@ const parseId = function (delta) {
 
 // Some stores shorten `id` and only keep the last 12 characters.
 const findById = function (metadataGroups, id) {
+  const idA = stripUuidDashes(id)
   return metadataGroups.findIndex(([firstMetadatum]) =>
-    id.endsWith(firstMetadatum.id),
+    idA.startsWith(firstMetadatum.id),
   )
 }
 

src/history/merge/id.js

@@ -37,14 +37,13 @@ export const getDefaultId = function () {
   return uuidv4()
 }
 
-// We only keep the last characters of the `result.id` in the filename.
+// We only keep the first characters of the `result.id` in the filename.
 // This is to keep filenames short since some systems impose a limit.
 // We keep it high enough to prevent collisions though.
 //  - 12 hexadecimal characters is 48 bits of entropy, which has a 50%
-//    probability of collision after 2e7 results with the same `id`, which is
-//    very unlikely
+//    probability of collision after 2e7 results
 export const shortenId = function (id) {
-  return id.slice(-ID_LENGTH)
+  return getUuidFirstChars(id, ID_LENGTH)
 }
 
 const ID_LENGTH = 12
@@ -55,10 +54,21 @@ const ID_LENGTH = 12
 // history results filenames are unique even when their `id` and `timestamp`
 // are the same (which is fairly unlikely).
 export const createSubId = function () {
-  const subId = uuidv4()
-  return subId.slice(-SUBID_LENGTH)
+  return getUuidFirstChars(uuidv4(), SUBID_LENGTH)
 }
 
 // This must be low enough to keep filenames short, but high enough to prevent
 // collisions
 const SUBID_LENGTH = 12
+
+const getUuidFirstChars = function (uuid, length) {
+  return stripUuidDashes(uuid).slice(0, length)
+}
+
+// Dashes are stripped from UUID to keep filenames short
+export const stripUuidDashes = function (uuid) {
+  return uuid.replace(DASH_REGEXP, '')
+}
+
+// TODO: use `String.replaceAll()` instead after dropping support for Node 14
+const DASH_REGEXP = /-/gu