From 6cc519b4c9a0868e89a2104de468db5cc6fd8d32 Mon Sep 17 00:00:00 2001
From: ehmicky <ehmicky@users.noreply.github.com>
Date: Thu, 9 May 2024 18:07:57 +0100
Subject: [PATCH] Fix complexity bug with types (#1037)

---
 types/stdio/direction.d.ts       | 12 +++---------
 types/stdio/type.d.ts            | 15 +++++++++++----
 types/transform/object-mode.d.ts |  7 ++-----
 types/utils.d.ts                 |  4 ++++
 4 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/types/stdio/direction.d.ts b/types/stdio/direction.d.ts
index 63541f4972..b58b89a916 100644
--- a/types/stdio/direction.d.ts
+++ b/types/stdio/direction.d.ts
@@ -1,5 +1,6 @@
 import type {CommonOptions} from '../arguments/options.js';
-import type {StdinOptionCommon, StdoutStderrOptionCommon, StdioOptionCommon} from './type.js';
+import type {Intersects} from '../utils.js';
+import type {StdioSingleOptionItems, InputStdioOption} from './type.js';
 import type {FdStdioArrayOption} from './option.js';
 
 // Whether `result.stdio[FdNumber]` is an input stream
@@ -8,11 +9,4 @@ export type IsInputFd<
 	OptionsType extends CommonOptions = CommonOptions,
 > = FdNumber extends '0'
 	? true
-	: IsInputDescriptor<FdStdioArrayOption<FdNumber, OptionsType>>;
-
-// Whether `result.stdio[3+]` is an input stream
-type IsInputDescriptor<StdioOptionType extends StdioOptionCommon> = StdioOptionType extends StdinOptionCommon
-	? StdioOptionType extends StdoutStderrOptionCommon
-		? false
-		: true
-	: false;
+	: Intersects<StdioSingleOptionItems<FdStdioArrayOption<FdNumber, OptionsType>>, InputStdioOption>;
diff --git a/types/stdio/type.d.ts b/types/stdio/type.d.ts
index 1a3ded7e56..5b890395bc 100644
--- a/types/stdio/type.d.ts
+++ b/types/stdio/type.d.ts
@@ -67,10 +67,10 @@ type ProcessStdinFd = {readonly fd?: 0};
 type ProcessStdoutStderrFd = {readonly fd?: 1 | 2};
 
 // Values available only in `options.stdin|stdio`
-type InputStdioOption<
-	IsSync extends boolean,
-	IsExtra extends boolean,
-	IsArray extends boolean,
+export type InputStdioOption<
+	IsSync extends boolean = boolean,
+	IsExtra extends boolean = boolean,
+	IsArray extends boolean = boolean,
 > =
 	| 0
 	| Unless<And<IsSync, IsExtra>, Uint8Array | IterableObject<IsArray>>
@@ -145,6 +145,13 @@ export type StdioSingleOption<
 	| StdinSingleOption<IsSync, IsExtra, IsArray>
 	| StdoutStderrSingleOption<IsSync, IsExtra, IsArray>;
 
+// Get `options.stdin|stdout|stderr|stdio` items if it is an array, else keep as is
+export type StdioSingleOptionItems<
+	StdioOptionType extends StdioOptionCommon,
+> = StdioOptionType extends readonly StdioSingleOption[]
+	? StdioOptionType[number]
+	: StdioOptionType;
+
 // `options.stdin|stdout|stderr|stdio`
 export type StdioOptionCommon<IsSync extends boolean = boolean> =
 	| StdinOptionCommon<IsSync>
diff --git a/types/transform/object-mode.d.ts b/types/transform/object-mode.d.ts
index 82f4619fea..1503f7c0ee 100644
--- a/types/transform/object-mode.d.ts
+++ b/types/transform/object-mode.d.ts
@@ -1,4 +1,4 @@
-import type {StdioSingleOption, StdioOptionCommon} from '../stdio/type.js';
+import type {StdioSingleOption, StdioOptionCommon, StdioSingleOptionItems} from '../stdio/type.js';
 import type {FdStdioOption} from '../stdio/option.js';
 import type {CommonOptions} from '../arguments/options.js';
 import type {DuplexTransform} from './normalize.js';
@@ -10,10 +10,7 @@ export type IsObjectFd<
 	OptionsType extends CommonOptions = CommonOptions,
 > = IsObjectStdioOption<FdStdioOption<FdNumber, OptionsType>>;
 
-type IsObjectStdioOption<StdioOptionType extends StdioOptionCommon> = IsObjectStdioSingleOption<StdioOptionType extends readonly StdioSingleOption[]
-	? StdioOptionType[number]
-	: StdioOptionType
->;
+type IsObjectStdioOption<StdioOptionType extends StdioOptionCommon> = IsObjectStdioSingleOption<StdioSingleOptionItems<StdioOptionType>>;
 
 type IsObjectStdioSingleOption<StdioSingleOptionType extends StdioSingleOption> = StdioSingleOptionType extends {objectMode?: boolean}
 	? BooleanObjectMode<StdioSingleOptionType['objectMode']>
diff --git a/types/utils.d.ts b/types/utils.d.ts
index 731d646ade..23871cf80e 100644
--- a/types/utils.d.ts
+++ b/types/utils.d.ts
@@ -7,3 +7,7 @@ export type Or<First extends boolean, Second extends boolean> = First extends tr
 export type Unless<Condition extends boolean, ThenValue, ElseValue = never> = Condition extends true ? ElseValue : ThenValue;
 
 export type AndUnless<Condition extends boolean, ThenValue, ElseValue = unknown> = Condition extends true ? ElseValue : ThenValue;
+
+// Whether any of T's union element is the same as one of U's union element.
+// `&` does not work here.
+export type Intersects<T, U> = true extends (T extends U ? true : false) ? true : false;