feat: add ctx.txt (#732)

src/context.ts

@@ -520,6 +520,15 @@ export class Context implements RenamedUpdate {
                 this.callbackQuery?.message
         );
     }
+    /**
+     * Get the message text from wherever possible. Alias for `this.msg?.text ??
+     * this.msg?.caption`.
+     */
+    get txt(): string | undefined {
+        // Keep in sync with types in `filter.ts`.
+        const msg = this.msg;
+        return msg?.text ?? msg?.caption;
+    }
     /**
      * Get the chat object from wherever possible. Alias for `(this.msg ??
      * this.deletedBusinessMessages ?? this.messageReaction ??

src/filter.ts

@@ -601,6 +601,9 @@ interface Shortcuts<U extends Update> {
         : [U["callback_query"]] extends [object]
             ? U["callback_query"]["message"]
         : undefined;
+    txt: [Shortcuts<U>["msg"]] extends [{ text: string } | { caption: string }]
+        ? string
+        : undefined;
     chat: [U["callback_query"]] extends [object]
         ? NonNullable<U["callback_query"]["message"]>["chat"] | undefined
         : [Shortcuts<U>["msg"]] extends [object] ? Shortcuts<U>["msg"]["chat"]

test/context.test.ts

@@ -147,6 +147,21 @@ describe("Context", () => {
         ctx = new Context(up, api, me);
         assertEquals(ctx.msg, up.edited_business_message);
     });
+    it(".txt should aggregate text", () => {
+        let up: Update, ctx: Context;
+        const mc = {
+            caption: "b",
+            from: u,
+            chat: c,
+            sender_chat: c,
+        } as Message;
+        up = { message: update.message } as Update;
+        ctx = new Context(up, api, me);
+        assertEquals(ctx.txt, up.message?.text);
+        up = { message: mc } as Update;
+        ctx = new Context(up, api, me);
+        assertEquals(ctx.txt, up.message?.caption);
+    });
 
     it(".chat should aggregate chats", () => {
         let up: Update, ctx: Context;

test/deps.test.ts

@@ -12,7 +12,11 @@ export {
 } from "jsr:@std/assert";
 export { afterEach, beforeEach, describe, it } from "jsr:@std/testing/bdd";
 export { type Spy, spy, type Stub, stub } from "jsr:@std/testing/mock";
-export { assertType, type IsExact } from "jsr:@std/testing/types";
+export {
+    assertType,
+    type IsExact,
+    type IsNullable,
+} from "jsr:@std/testing/types";
 export { type IsMutuallyAssignable } from "jsr:@std/testing/unstable-types";
 
 /**

test/filter.test.ts

@@ -3,7 +3,9 @@ import {
     assert,
     assertEquals,
     assertThrows,
+    assertType,
     describe,
+    type IsNullable,
     it,
 } from "./deps.test.ts";
 
@@ -143,4 +145,25 @@ describe("matchFilter", () => {
             throw "never";
         }
     });
+
+    it("should narrow down context shortcut types", () => {
+        const ctx = new Context(
+            // deno-lint-ignore no-explicit-any
+            {} as any,
+            // deno-lint-ignore no-explicit-any
+            undefined as any,
+            // deno-lint-ignore no-explicit-any
+            undefined as any,
+        );
+        if (matchFilter([":text", ":caption"])(ctx)) {
+            assertType<IsNullable<typeof ctx["msg"]>>(false);
+            assertType<IsNullable<typeof ctx["txt"]>>(false);
+            assertType<IsNullable<typeof ctx["chat"]>>(false);
+            assertType<IsNullable<typeof ctx["msgId"]>>(false);
+            assertType<IsNullable<typeof ctx["chatId"]>>(false);
+        }
+        if (matchFilter("message")(ctx)) {
+            assertType<IsNullable<typeof ctx["from"]>>(false);
+        }
+    });
 });