fix: prevent assigning UUIDs to different versions

This change stores the UUID version as a phantom type so that it's no longer possible to assign a UUID version 1 to a UUID version 2, for example.
thewilkybarkid · Apr 5, 2022 · 7f70616 · 7f70616
1 parent 5f5940a
commit 7f70616
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/src/index.ts b/src/index.ts
@@ -10,10 +10,11 @@
  * @category model
  * @since 0.1.0
  */
-export type Uuid<V extends UuidVersion = UuidVersion> = string & UuidBrand
+export type Uuid<V extends UuidVersion = UuidVersion> = string & UuidBrand<V>
 
 type UuidVersion = 1 | 2 | 3 | 4 | 5
 
-interface UuidBrand {
+interface UuidBrand<V extends UuidVersion> {
+  readonly _V: V
   readonly Uuid: unique symbol
 }
diff --git a/test-d/ts4.0/index.ts b/test-d/ts4.0/index.ts
@@ -17,3 +17,8 @@ declare const uuid6: _.Uuid<6>
 const uuidToString: string = uuid
 // $ExpectError
 const stringToUuid: _.Uuid = 'foo'
+const uuid1ToUuid: _.Uuid = uuid1
+// $ExpectError
+const uuidToUuid1: _.Uuid<1> = uuid
+// $ExpectError
+const uuid1toUuid2: _.Uuid<2> = uuid1