types(util): add case utility types (#683)

* types(util): add case utility types

* Rename *ID to *Id

.github/CONTRIBUTING.md

@@ -66,9 +66,9 @@ Examples of bad PR title:
 Example:
 
 ```ts
-// Discordeno has utility type Camelize<T>, where T is an interface with keys in snake case.
+// Discordeno has utility type CamelCaseProps<T>, where T is an interface with keys in snake case.
 // It can be used to "generate" corresponding "Discordeno type" from "Discord type".
-// Example: export type BanOptions = Camelize<DiscordBanOptions>
+// Example: export type BanOptions = CamelCaseProps<DiscordBanOptions>
 
 export interface EditMemberOptions {
   /** Value to set users nickname to. Requires MANAGE_NICKNAMES permission. */

src/handlers/commands/APPLICATION_COMMAND_CREATE.ts

@@ -5,14 +5,14 @@ export function handleApplicationCommandCreate(
   data: DiscordPayload,
 ) {
   const {
-    guild_id: guildID,
-    application_id: applicationID,
+    guild_id: guildId,
+    application_id: applicationId,
     ...rest
   } = data.d as ApplicationCommandEvent;
 
   eventHandlers.applicationCommandCreate?.({
     ...rest,
-    guildID,
-    applicationID,
+    guildId,
+    applicationId,
   });
 }

src/handlers/commands/APPLICATION_COMMAND_DELETE.ts

@@ -3,14 +3,14 @@ import { ApplicationCommandEvent, DiscordPayload } from "../../types/mod.ts";
 
 export function handleApplicationCommandDelete(data: DiscordPayload) {
   const {
-    application_id: applicationID,
-    guild_id: guildID,
+    application_id: applicationId,
+    guild_id: guildId,
     ...rest
   } = data.d as ApplicationCommandEvent;
 
   eventHandlers.applicationCommandDelete?.({
     ...rest,
-    guildID,
-    applicationID,
+    guildId,
+    applicationId,
   });
 }

src/handlers/commands/APPLICATION_COMMAND_UPDATE.ts

@@ -3,14 +3,14 @@ import { ApplicationCommandEvent, DiscordPayload } from "../../types/mod.ts";
 
 export function handleApplicationCommandUpdate(data: DiscordPayload) {
   const {
-    application_id: applicationID,
-    guild_id: guildID,
+    application_id: applicationId,
+    guild_id: guildId,
     ...rest
   } = data.d as ApplicationCommandEvent;
 
   eventHandlers.applicationCommandUpdate?.({
     ...rest,
-    guildID,
-    applicationID,
+    guildId,
+    applicationId,
   });
 }

src/handlers/integrations/INTEGRATION_CREATE.ts

@@ -8,24 +8,24 @@ export function handleIntegrationCreate(
   data: DiscordPayload,
 ) {
   const {
-    guild_id: guildID,
+    guild_id: guildId,
     enable_emoticons: enableEmoticons,
     expire_behavior: expireBehavior,
     expire_grace_period: expireGracePeriod,
     subscriber_count: subscriberCount,
-    role_id: roleID,
+    role_id: roleId,
     synced_at: syncedAt,
     ...rest
   } = data.d as IntegrationCreateUpdateEvent;
 
   eventHandlers.integrationCreate?.({
     ...rest,
-    guildID,
+    guildId,
     enableEmoticons,
     expireBehavior,
     expireGracePeriod,
     syncedAt,
     subscriberCount,
-    roleID,
+    roleId,
   });
 }

src/handlers/integrations/INTEGRATION_DELETE.ts

@@ -3,14 +3,14 @@ import { DiscordPayload, IntegrationDeleteEvent } from "../../types/mod.ts";
 
 export function handleIntegrationDelete(data: DiscordPayload) {
   const {
-    guild_id: guildID,
-    application_id: applicationID,
+    guild_id: guildId,
+    application_id: applicationId,
     ...rest
   } = data.d as IntegrationDeleteEvent;
 
   eventHandlers.integrationDelete?.({
     ...rest,
-    applicationID,
-    guildID,
+    applicationId,
+    guildId,
   });
 }

src/handlers/integrations/INTEGRATION_UPDATE.ts

@@ -9,20 +9,20 @@ export function handleIntegrationUpdate(data: DiscordPayload) {
     enable_emoticons: enableEmoticons,
     expire_behavior: expireBehavior,
     expire_grace_period: expireGracePeriod,
-    role_id: roleID,
+    role_id: roleId,
     subscriber_count: subscriberCount,
     synced_at: syncedAt,
-    guild_id: guildID,
+    guild_id: guildId,
     ...rest
   } = data.d as IntegrationCreateUpdateEvent;
 
   eventHandlers.integrationUpdate?.({
     ...rest,
-    guildID,
+    guildId,
     subscriberCount,
     enableEmoticons,
     expireGracePeriod,
-    roleID,
+    roleId,
     expireBehavior,
     syncedAt,
   });

src/handlers/invites/INVITE_CREATE.ts

@@ -5,10 +5,10 @@ export function handleInviteCreate(payload: DiscordPayload) {
   if (payload.t !== "INVITE_CREATE") return;
   //TODO: replace with tocamelcase
   const {
-    channel_id: channelID,
+    channel_id: channelId,
     created_at: createdAt,
     max_age: maxAge,
-    guild_id: guildID,
+    guild_id: guildId,
     target_user: targetUser,
     target_user_type: targetUserType,
     max_uses: maxUses,
@@ -17,8 +17,8 @@ export function handleInviteCreate(payload: DiscordPayload) {
 
   eventHandlers.inviteCreate?.({
     ...rest,
-    channelID,
-    guildID,
+    channelId,
+    guildId,
     maxAge,
     targetUser,
     targetUserType,

src/types/options.ts

@@ -25,7 +25,7 @@ import {
   PartialMessage,
   ReactionPayload,
 } from "./message.ts";
-import { Camelize } from "./util.ts";
+import { CamelCaseProps } from "./util.ts";
 
 export interface BotConfig {
   token: string;
@@ -93,15 +93,15 @@ export interface EventHandlers {
   rateLimit?: (data: RateLimitData) => unknown;
   /** Sent when a new Slash Command is created, relevant to the current user. */
   applicationCommandCreate?: (
-    data: Camelize<ApplicationCommandEvent>,
+    data: CamelCaseProps<ApplicationCommandEvent>,
   ) => unknown;
   /** Sent when a Slash Command relevant to the current user is updated. */
   applicationCommandUpdate?: (
-    data: Camelize<ApplicationCommandEvent>,
+    data: CamelCaseProps<ApplicationCommandEvent>,
   ) => unknown;
   /** Sent when a Slash Command relevant to the current user is deleted. */
   applicationCommandDelete?: (
-    data: Camelize<ApplicationCommandEvent>,
+    data: CamelCaseProps<ApplicationCommandEvent>,
   ) => unknown;
   /** Sent when properties about the user change. */
   botUpdate?: (user: UserPayload) => unknown;
@@ -242,15 +242,21 @@ export interface EventHandlers {
   /** Sent when a member has passed the guild's Membership Screening requirements */
   membershipScreeningPassed?: (guild: Guild, member: Member) => unknown;
   /** Sent when an integration is created on a server such as twitch, youtube etc.. */
-  integrationCreate?: (data: Camelize<IntegrationCreateUpdateEvent>) => unknown;
+  integrationCreate?: (
+    data: CamelCaseProps<IntegrationCreateUpdateEvent>,
+  ) => unknown;
   /** Sent when an integration is updated. */
-  integrationUpdate?: (data: Camelize<IntegrationCreateUpdateEvent>) => unknown;
+  integrationUpdate?: (
+    data: CamelCaseProps<IntegrationCreateUpdateEvent>,
+  ) => unknown;
   /** Sent when an integration is deleted. */
-  integrationDelete?: (data: Camelize<IntegrationDeleteEvent>) => undefined;
+  integrationDelete?: (
+    data: CamelCaseProps<IntegrationDeleteEvent>,
+  ) => undefined;
   /** Sent when a new invite to a channel is created. */
-  inviteCreate?: (data: Camelize<InviteCreateEvent>) => unknown;
+  inviteCreate?: (data: CamelCaseProps<InviteCreateEvent>) => unknown;
   /** Sent when an invite is deleted. */
-  inviteDelete?: (data: Camelize<InviteDeleteEvent>) => unknown;
+  inviteDelete?: (data: CamelCaseProps<InviteDeleteEvent>) => unknown;
 }
 
 /** https://discord.com/developers/docs/topics/gateway#list-of-intents */

src/types/util.ts

@@ -1,10 +1,117 @@
-export type CamelizeString<T extends PropertyKey> = T extends string
-  ? string extends T ? string
-  : T extends `${infer F}_${infer R}`
-    ? `${F}${T extends `${infer F}_id` ? Uppercase<R>
-      : Capitalize<CamelizeString<R>>}`
-  : T
-  : T;
+type UpperCaseCharacters =
+  | "A"
+  | "B"
+  | "C"
+  | "D"
+  | "E"
+  | "F"
+  | "G"
+  | "H"
+  | "I"
+  | "J"
+  | "K"
+  | "L"
+  | "M"
+  | "N"
+  | "O"
+  | "P"
+  | "Q"
+  | "R"
+  | "S"
+  | "T"
+  | "U"
+  | "V"
+  | "W"
+  | "X"
+  | "Y"
+  | "Z";
 
-// deno-fmt-ignore
-export type Camelize<T> = { [K in keyof T as CamelizeString<K>]: T[K] };
+type WordSeparators = "-" | "_" | " ";
+
+type SplitIncludingDelimiters<
+  Source extends string,
+  Delimiter extends string,
+> = Source extends "" ? []
+  : Source extends `${infer FirstPart}${Delimiter}${infer SecondPart}` ? (
+    Source extends `${FirstPart}${infer UsedDelimiter}${SecondPart}`
+      ? UsedDelimiter extends Delimiter
+        ? Source extends `${infer FirstPart}${UsedDelimiter}${infer SecondPart}`
+          ? [
+            ...SplitIncludingDelimiters<FirstPart, Delimiter>,
+            UsedDelimiter,
+            ...SplitIncludingDelimiters<SecondPart, Delimiter>,
+          ]
+        : never
+      : never
+      : never
+  )
+  : [Source];
+type StringPartToDelimiterCase<
+  StringPart extends string,
+  UsedWordSeparators extends string,
+  UsedUpperCaseCharacters extends string,
+  Delimiter extends string,
+> = StringPart extends UsedWordSeparators ? Delimiter
+  : StringPart extends UsedUpperCaseCharacters
+    ? `${Delimiter}${Lowercase<StringPart>}`
+  : StringPart;
+type StringArrayToDelimiterCase<
+  Parts extends any[],
+  UsedWordSeparators extends string,
+  UsedUpperCaseCharacters extends string,
+  Delimiter extends string,
+> = Parts extends [`${infer FirstPart}`, ...infer RemainingParts]
+  ? `${StringPartToDelimiterCase<
+    FirstPart,
+    UsedWordSeparators,
+    UsedUpperCaseCharacters,
+    Delimiter
+  >}${StringArrayToDelimiterCase<
+    RemainingParts,
+    UsedWordSeparators,
+    UsedUpperCaseCharacters,
+    Delimiter
+  >}`
+  : "";
+type DelimiterCase<Value, Delimiter extends string> = Value extends string
+  ? StringArrayToDelimiterCase<
+    SplitIncludingDelimiters<Value, WordSeparators | UpperCaseCharacters>,
+    WordSeparators,
+    UpperCaseCharacters,
+    Delimiter
+  >
+  : Value;
+type InnerCamelCaseStringArray<Parts extends any[], PreviousPart> =
+  Parts extends [`${infer FirstPart}`, ...infer RemainingParts]
+    ? FirstPart extends undefined ? ""
+    : FirstPart extends ""
+      ? InnerCamelCaseStringArray<RemainingParts, PreviousPart>
+    : `${PreviousPart extends "" ? FirstPart
+      : Capitalize<FirstPart>}${InnerCamelCaseStringArray<
+      RemainingParts,
+      FirstPart
+    >}`
+    : "";
+type CamelCaseStringArray<Parts extends string[]> = Parts extends
+  [`${infer FirstPart}`, ...infer RemainingParts] ? Uncapitalize<
+  `${FirstPart}${InnerCamelCaseStringArray<RemainingParts, FirstPart>}`
+>
+  : never;
+type Split<S extends string, D extends string> = string extends S ? string[]
+  : S extends "" ? []
+  : S extends `${infer T}${D}${infer U}` ? [T, ...Split<U, D>]
+  : [S];
+
+export type SnakeCase<Value> = DelimiterCase<Value, "_">;
+
+export type CamelCase<K> = K extends string
+  ? CamelCaseStringArray<Split<K, WordSeparators>>
+  : K;
+
+export type CamelCaseProps<T> = {
+  [K in keyof T as CamelCase<K>]: T[K];
+};
+
+export type SnakeCaseProps<T> = {
+  [K in keyof T as SnakeCase<K>]: T[K];
+};