1 files changed, 16 insertions, 0 deletions
diff --git a/src/alf/types.ts b/src/alf/types.ts
new file mode 100644
index 000000000..76ac05d40
--- /dev/null
+++ b/src/alf/types.ts
@@ -0,0 +1,16 @@
+type LiteralToCommon<T extends PropertyKey> = T extends number
+  ? number
+  : T extends string
+  ? string
+  : T extends symbol
+  ? symbol
+  : never
+
+/**
+ * @see https://stackoverflow.com/questions/68249999/use-as-const-in-typescript-without-adding-readonly-modifiers
+ */
+export type Mutable<T> = {
+  -readonly [K in keyof T]: T[K] extends PropertyKey
+    ? LiteralToCommon<T[K]>
+    : Mutable<T[K]>
+}