From a485ebaf74176c52d36f99ad9b33eda6284c07c5 Mon Sep 17 00:00:00 2001
From: itsMapleLeaf <19603573+itsMapleLeaf@users.noreply.github.com>
Date: Sun, 24 Apr 2022 16:05:00 -0500
Subject: [PATCH] improve pruneNullishValues + test

---
 .../helpers/prune-nullish-values.test.ts      | 33 +++++++++++++++++++
 .../reacord/helpers/prune-nullish-values.ts   | 27 +++++++++++----
 2 files changed, 54 insertions(+), 6 deletions(-)
 create mode 100644 packages/reacord/helpers/prune-nullish-values.test.ts

diff --git a/packages/reacord/helpers/prune-nullish-values.test.ts b/packages/reacord/helpers/prune-nullish-values.test.ts
new file mode 100644
index 0000000..aedbe2e
--- /dev/null
+++ b/packages/reacord/helpers/prune-nullish-values.test.ts
@@ -0,0 +1,33 @@
+import { expect, test } from "vitest"
+import { PruneNullishValues, pruneNullishValues } from "./prune-nullish-values"
+
+test("pruneNullishValues", () => {
+  type InputType = {
+    a: string
+    b: string | null | undefined
+    c?: string
+    d: {
+      a: string
+      b: string | undefined
+    }
+  }
+
+  const input: InputType = {
+    a: "a",
+    b: null,
+    c: undefined,
+    d: {
+      a: "a",
+      b: undefined,
+    },
+  }
+
+  const output: PruneNullishValues<InputType> = {
+    a: "a",
+    d: {
+      a: "a",
+    },
+  }
+
+  expect(pruneNullishValues(input)).toEqual(output)
+})
diff --git a/packages/reacord/helpers/prune-nullish-values.ts b/packages/reacord/helpers/prune-nullish-values.ts
index 2729990..0324dc6 100644
--- a/packages/reacord/helpers/prune-nullish-values.ts
+++ b/packages/reacord/helpers/prune-nullish-values.ts
@@ -18,10 +18,25 @@ export function pruneNullishValues<T>(input: T): PruneNullishValues<T> {
   return result
 }
 
-type PruneNullishValues<Input> = Input extends ReadonlyArray<infer Value>
-  ? ReadonlyArray<NonNullable<Value>>
-  : Input extends object
-  ? {
-      [Key in keyof Input]: NonNullable<Input[Key]>
-    }
+export type PruneNullishValues<Input> = Input extends object
+  ? OptionalKeys<
+      { [Key in keyof Input]: NonNullable<PruneNullishValues<Input[Key]>> },
+      KeysWithNullishValues<Input>
+    >
   : Input
+
+type OptionalKeys<Input, Keys extends keyof Input> = Omit<Input, Keys> & {
+  [Key in Keys]?: Input[Key]
+}
+
+type KeysWithNullishValues<Input> = NonNullable<
+  Values<{
+    [Key in keyof Input]: null extends Input[Key]
+      ? Key
+      : undefined extends Input[Key]
+      ? Key
+      : never
+  }>
+>
+
+type Values<Input> = Input[keyof Input]