From b3f7c32f7f91f12766178f5e17585856e81d9a87 Mon Sep 17 00:00:00 2001
From: Jiralite <33201955+Jiralite@users.noreply.github.com>
Date: Sat, 20 Aug 2022 21:29:16 +0100
Subject: [PATCH] types: Allow choice's value type to be strictly inferred
 (#8529)

* types: stricter types for choices in options

* test: add choice tests

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>
---
 packages/discord.js/typings/index.d.ts      | 24 ++++++++++-----------
 packages/discord.js/typings/index.test-d.ts | 19 ++++++++++++++++
 2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/packages/discord.js/typings/index.d.ts b/packages/discord.js/typings/index.d.ts
index ac715ff647c5..61e6935a78a9 100644
--- a/packages/discord.js/typings/index.d.ts
+++ b/packages/discord.js/typings/index.d.ts
@@ -3873,19 +3873,21 @@ export interface ApplicationCommandAutocompleteStringOptionData
   autocomplete: true;
 }
 
-export interface ApplicationCommandChoicesData extends Omit<BaseApplicationCommandOptionsData, 'autocomplete'> {
+export interface ApplicationCommandChoicesData<Type extends string | number = string | number>
+  extends Omit<BaseApplicationCommandOptionsData, 'autocomplete'> {
   type: CommandOptionChoiceResolvableType;
-  choices?: ApplicationCommandOptionChoiceData[];
+  choices?: ApplicationCommandOptionChoiceData<Type>[];
   autocomplete?: false;
 }
 
-export interface ApplicationCommandChoicesOption extends Omit<BaseApplicationCommandOptionsData, 'autocomplete'> {
+export interface ApplicationCommandChoicesOption<Type extends string | number = string | number>
+  extends Omit<BaseApplicationCommandOptionsData, 'autocomplete'> {
   type: CommandOptionChoiceResolvableType;
-  choices?: ApplicationCommandOptionChoiceData[];
+  choices?: ApplicationCommandOptionChoiceData<Type>[];
   autocomplete?: false;
 }
 
-export interface ApplicationCommandNumericOptionData extends ApplicationCommandChoicesData {
+export interface ApplicationCommandNumericOptionData extends ApplicationCommandChoicesData<number> {
   type: CommandOptionNumericResolvableType;
   minValue?: number;
   min_value?: number;
@@ -3893,7 +3895,7 @@ export interface ApplicationCommandNumericOptionData extends ApplicationCommandC
   max_value?: number;
 }
 
-export interface ApplicationCommandStringOptionData extends ApplicationCommandChoicesData {
+export interface ApplicationCommandStringOptionData extends ApplicationCommandChoicesData<string> {
   type: ApplicationCommandOptionType.String;
   minLength?: number;
   min_length?: number;
@@ -3905,13 +3907,13 @@ export interface ApplicationCommandBooleanOptionData extends BaseApplicationComm
   type: ApplicationCommandOptionType.Boolean;
 }
 
-export interface ApplicationCommandNumericOption extends ApplicationCommandChoicesOption {
+export interface ApplicationCommandNumericOption extends ApplicationCommandChoicesOption<number> {
   type: CommandOptionNumericResolvableType;
   minValue?: number;
   maxValue?: number;
 }
 
-export interface ApplicationCommandStringOption extends ApplicationCommandChoicesOption {
+export interface ApplicationCommandStringOption extends ApplicationCommandChoicesOption<string> {
   type: ApplicationCommandOptionType.String;
   minLength?: number;
   maxLength?: number;
@@ -3953,7 +3955,6 @@ export type ApplicationCommandOptionData =
   | ApplicationCommandSubGroupData
   | ApplicationCommandNonOptionsData
   | ApplicationCommandChannelOptionData
-  | ApplicationCommandChoicesData
   | ApplicationCommandAutocompleteNumericOptionData
   | ApplicationCommandAutocompleteStringOptionData
   | ApplicationCommandNumericOptionData
@@ -3970,7 +3971,6 @@ export type ApplicationCommandOption =
   | ApplicationCommandAutocompleteStringOption
   | ApplicationCommandNonOptions
   | ApplicationCommandChannelOption
-  | ApplicationCommandChoicesOption
   | ApplicationCommandNumericOption
   | ApplicationCommandStringOption
   | ApplicationCommandRoleOption
@@ -3980,10 +3980,10 @@ export type ApplicationCommandOption =
   | ApplicationCommandAttachmentOption
   | ApplicationCommandSubCommand;
 
-export interface ApplicationCommandOptionChoiceData {
+export interface ApplicationCommandOptionChoiceData<Value extends string | number = string | number> {
   name: string;
   nameLocalizations?: LocalizationMap;
-  value: string | number;
+  value: Value;
 }
 
 export interface ApplicationCommandPermissions {
diff --git a/packages/discord.js/typings/index.test-d.ts b/packages/discord.js/typings/index.test-d.ts
index 4b18299d56e2..995c60ae4b56 100644
--- a/packages/discord.js/typings/index.test-d.ts
+++ b/packages/discord.js/typings/index.test-d.ts
@@ -1102,6 +1102,7 @@ expectAssignable<'death'>(ShardEvents.Death);
 expectAssignable<1>(Status.Connecting);
 
 declare const applicationCommandData: ApplicationCommandData;
+declare const applicationCommandOptionData: ApplicationCommandOptionData;
 declare const applicationCommandResolvable: ApplicationCommandResolvable;
 declare const applicationCommandManager: ApplicationCommandManager;
 {
@@ -1121,6 +1122,24 @@ declare const applicationCommandManager: ApplicationCommandManager;
   expectType<Promise<Collection<Snowflake, ApplicationCommand>>>(
     applicationCommandManager.set([applicationCommandData], '0'),
   );
+
+  // Test inference of choice values.
+  if ('choices' in applicationCommandOptionData) {
+    if (applicationCommandOptionData.type === ApplicationCommandOptionType.String) {
+      expectType<string>(applicationCommandOptionData.choices[0]!.value);
+      expectNotType<number>(applicationCommandOptionData.choices[0]!.value);
+    }
+
+    if (applicationCommandOptionData.type === ApplicationCommandOptionType.Integer) {
+      expectType<number>(applicationCommandOptionData.choices[0]!.value);
+      expectNotType<string>(applicationCommandOptionData.choices[0]!.value);
+    }
+
+    if (applicationCommandOptionData.type === ApplicationCommandOptionType.Number) {
+      expectType<number>(applicationCommandOptionData.choices[0]!.value);
+      expectNotType<string>(applicationCommandOptionData.choices[0]!.value);
+    }
+  }
 }
 
 declare const applicationNonChoiceOptionData: ApplicationCommandOptionData & {