add distributiveomit utility type and use it for say and respond argu…

…ments. fix up getting started typescript example

examples/getting-started-typescript/package.json

@@ -11,7 +11,7 @@
   "license": "MIT",
   "dependencies": {
     "@slack/bolt": "^3.3.0",
-    "dotenv": "^8.2.0"
+    "dotenv": "^16"
   },
   "devDependencies": {
     "@tsconfig/node18": "^18.2.4",

examples/getting-started-typescript/src/basic.ts

@@ -119,7 +119,7 @@ app.action<BlockAction>({ action_id: 'select_user', block_id: 'assign_ticket' },
         await client.reactions.add({
           name: 'white_check_mark',
           timestamp: body.message?.ts,
-          channel: body.channel?.id,
+          channel: body.channel!.id, // if the body has a message, we know it has a channel, too.
         });
       }
     } catch (error) {

src/types/utilities.ts

@@ -6,19 +6,22 @@ export const isFulfilled = <T>(p:PromiseSettledResult<T>): p is PromiseFulfilled
 /** Type predicate for use with `Promise.allSettled` for filtering for rejected results. */
 export const isRejected = <T>(p:PromiseSettledResult<T>): p is PromiseRejectedResult => p.status === 'rejected';
 
-// TODO: consider moving the following types closer to relevant code
+/** Using type parameter T (generic), can distribute the Omit over a union set. */
+type DistributiveOmit<T, K extends PropertyKey> = T extends any
+  ? Omit<T, K>
+  : never;
+
 // The say() utility function binds the message to the same channel as the incoming message that triggered the
 // listener. Therefore, specifying the `channel` argument is not required.
-export type SayArguments = Omit<ChatPostMessageArguments, 'channel'> & {
+export type SayArguments = DistributiveOmit<ChatPostMessageArguments, 'channel'> & {
   // TODO: This will be overwritten in the `createSay` factory method in App.ts anyways, so why include it?
   channel?: string;
 };
-
 export interface SayFn {
   (message: string | SayArguments): Promise<ChatPostMessageResponse>;
 }
 
-export type RespondArguments = Omit<ChatPostMessageArguments, 'channel' | 'text'>
+export type RespondArguments = DistributiveOmit<ChatPostMessageArguments, 'channel' | 'text'>
 & {
   /** Response URLs can be used to send ephemeral messages or in-channel messages using this argument */
   response_type?: 'in_channel' | 'ephemeral';

tsconfig.json

@@ -6,6 +6,7 @@
     "declarationMap": true,
     "module": "CommonJS",
     "moduleResolution": "node",
+    "noErrorTruncation": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "noImplicitReturns": true,

types-tests/action.test-d.ts

@@ -1,5 +1,5 @@
 import { expectError, expectType } from 'tsd';
-import { App, BlockElementAction, InteractiveAction, DialogSubmitAction } from '../';
+import { App, BlockElementAction, InteractiveAction, DialogSubmitAction } from '..';
 
 const app = new App({ token: 'TOKEN', signingSecret: 'Signing Secret' });
 

types-tests/utilities.test-d.ts

@@ -1,6 +1,8 @@
 import { expectType } from 'tsd';
 import { ChatPostMessageResponse } from '@slack/web-api';
-import { App, InteractiveButtonClick } from '..';
+// eslint-disable-next-line
+import App from '../src/App';
+import { InteractiveButtonClick } from '../src/types';
 
 const app = new App({ token: 'TOKEN', signingSecret: 'Signing Secret' });