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>
discordjs · Aug 20, 2022 · b3f7c32 · b3f7c32
1 parent 0dba8ad
commit b3f7c32
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Showing 2 changed files with 31 additions and 12 deletions.
diff --git a/packages/discord.js/typings/index.d.ts b/packages/discord.js/typings/index.d.ts
@@ -3873,27 +3873,29 @@ 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;
   maxValue?: number;
   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
@@ -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 & {