feat: create*Event methods now return strings (copilot-extensions#59)

BREAKING CHANGE: All `create*Event` methods now return a string instead
of an object with a `.toString()` method.

Before:

```js
esponse.write(createTextEvent("Hello, world!").toString());
```

Now:

```js
esponse.write(createTextEvent("Hello, world!"));
```

Author: gr2m

README.md

@@ -46,9 +46,9 @@ export default handler(request, response) {
   const textEvent = createTextEvent("Hello, world!");
   const doneEvent = createDoneEvent();
 
-  response.write(ackEvent.toString());
-  response.write(textEvent.toString());
-  response.end(doneEvent.toString());
+  response.write(ackEvent);
+  response.write(textEvent);
+  response.end(doneEvent);
 }
 ```
 
@@ -131,7 +131,7 @@ const payloadIsVerified = await verifyRequestPayload(
 
 ### Response
 
-All `create*Event()` methods return an object with a `.toString()` method, which is called automatically when a string is expected. Unfortunately that's not the case for `response.write()`, you need to call `.toString()` explicitly.
+All `create*Event()` methods return a string that can directly be written to the response stream.
 
 #### `createAckEvent()`
 
@@ -141,7 +141,7 @@ The `ack` event should only be sent once.
 ```js
 import { createAckEvent } from "@copilot-extensions/preview-sdk";
 
-response.write(createAckEvent().toString());
+response.write(createAckEvent());
 ```
 
 #### `createTextEvent(message)`
@@ -151,8 +151,8 @@ Send a text message to the chat UI. Multiple messages can be sent. The `message`
 ```js
 import { createTextEvent } from "@copilot-extensions/preview-sdk";
 
-response.write(createTextEvent("Hello, world!").toString());
-response.write(createTextEvent("Hello, again!").toString());
+response.write(createTextEvent("Hello, world!"));
+response.write(createTextEvent("Hello, again!"));
 ```
 
 #### `createConfirmationEvent({ id, title, message, metadata })`
@@ -171,7 +171,7 @@ response.write(
     id: "123",
     title: "Are you sure?",
     message: "This will do something.",
-  }).toString(),
+  }),
 );
 ```
 
@@ -209,7 +209,7 @@ response.write(
         display_icon: "issue-opened",
         display_url: "https://github.com/monalisa/hello-world/issues/123",
     },
-  ]).toString()
+  ])
 );
 ```
 
@@ -231,7 +231,7 @@ The `done` event should only be sent once, at the end of the response. No furthe
 ```js
 import { createDoneEvent } from "@copilot-extensions/preview-sdk";
 
-response.write(createDoneEvent().toString());
+response.write(createDoneEvent());
 ```
 
 ### Parsing

index.d.ts

@@ -33,11 +33,10 @@ interface VerifyRequestByKeyIdInterface {
 // response types
 
 export interface CreateAckEventInterface {
-  (): ResponseEvent<"ack">;
+  (): string;
 }
-
 export interface CreateTextEventInterface {
-  (message: string): ResponseEvent<"text">;
+  (message: string): string;
 }
 
 export type CreateConfirmationEventOptions = {
@@ -50,88 +49,18 @@ export type CreateConfirmationEventOptions = {
 export interface CreateConfirmationEventInterface {
   (
     options: CreateConfirmationEventOptions,
-  ): ResponseEvent<"copilot_confirmation">;
+  ): string;
 }
 export interface CreateReferencesEventInterface {
-  (references: CopilotReference[]): ResponseEvent<"copilot_references">;
+  (references: CopilotReference[]): string;
 }
 export interface CreateErrorsEventInterface {
-  (errors: CopilotError[]): ResponseEvent<"copilot_errors">;
+  (errors: CopilotError[]): string;
 }
 export interface CreateDoneEventInterface {
-  (): ResponseEvent<"done">;
+  (): string;
 }
 
-type ResponseEventType =
-  | "ack"
-  | "done"
-  | "text"
-  | "copilot_references"
-  | "copilot_confirmation"
-  | "copilot_errors";
-type EventsWithoutEventKey = "ack" | "done" | "text";
-type ResponseEvent<T extends ResponseEventType = "text"> =
-  T extends EventsWithoutEventKey
-    ? {
-        data: T extends "ack"
-          ? CopilotAckResponseEventData
-          : T extends "done"
-            ? CopilotDoneResponseEventData
-            : T extends "text"
-              ? CopilotTextResponseEventData
-              : never;
-        toString: () => string;
-      }
-    : {
-        event: T;
-        data: T extends "copilot_references"
-          ? CopilotReferenceResponseEventData
-          : T extends "copilot_confirmation"
-            ? CopilotConfirmationResponseEventData
-            : T extends "copilot_errors"
-              ? CopilotErrorsResponseEventData
-              : never;
-        toString: () => string;
-      };
-
-type CopilotAckResponseEventData = {
-  choices: [
-    {
-      delta: InteropMessage<"assistant">;
-    },
-  ];
-};
-
-type CopilotDoneResponseEventData = {
-  choices: [
-    {
-      finish_reason: "stop";
-      delta: {
-        content: null;
-      };
-    },
-  ];
-};
-
-type CopilotTextResponseEventData = {
-  choices: [
-    {
-      delta: InteropMessage<"assistant">;
-    },
-  ];
-};
-type CopilotConfirmationResponseEventData = {
-  type: "action";
-  title: string;
-  message: string;
-  confirmation?: {
-    id: string;
-    [key: string]: any;
-  };
-};
-type CopilotErrorsResponseEventData = CopilotError[];
-type CopilotReferenceResponseEventData = CopilotReference[];
-
 type CopilotError = {
   type: "reference" | "function" | "agent";
   code: string;

index.test-d.ts

@@ -87,36 +87,12 @@ export async function fetchVerificationKeysTest() {
 
 export function createAckEventTest() {
   const event = createAckEvent();
-  expectType<() => string>(event.toString);
-  expectType<string>(event.toString());
-
-  expectType<{
-    choices: [
-      {
-        delta: InteropMessage<"assistant">;
-      },
-    ];
-  }>(event.data);
-
-  // @ts-expect-error - .event is required
-  event.event;
+  expectType<string>(event);
 }
 
 export function createTextEventTest() {
   const event = createTextEvent("test");
-  expectType<() => string>(event.toString);
-  expectType<string>(event.toString());
-
-  expectType<{
-    choices: [
-      {
-        delta: InteropMessage<"assistant">;
-      },
-    ];
-  }>(event.data);
-
-  // @ts-expect-error - .event is required
-  event.event;
+  expectType<string>(event);
 }
 
 export function createConfirmationEventTest() {
@@ -125,31 +101,7 @@ export function createConfirmationEventTest() {
     title: "test",
     message: "test",
   });
-
-  // optional metadata
-  createConfirmationEvent({
-    id: "test",
-    title: "test",
-    message: "test",
-    metadata: {
-      someOtherId: "test",
-    },
-  });
-
-  expectType<() => string>(event.toString);
-  expectType<string>(event.toString());
-
-  expectType<{
-    type: "action";
-    title: string;
-    message: string;
-    confirmation?: {
-      id: string;
-      [key: string]: any;
-    };
-  }>(event.data);
-
-  expectType<"copilot_confirmation">(event.event);
+  expectType<string>(event);
 }
 
 export function createReferencesEventTest() {
@@ -172,26 +124,7 @@ export function createReferencesEventTest() {
       },
     },
   ]);
-  expectType<() => string>(event.toString);
-  expectType<string>(event.toString());
-
-  expectType<
-    {
-      type: string;
-      id: string;
-      data?: {
-        [key: string]: unknown;
-      };
-      is_implicit?: boolean;
-      metadata?: {
-        display_name: string;
-        display_icon?: string;
-        display_url?: string;
-      };
-    }[]
-  >(event.data);
-
-  expectType<"copilot_references">(event.event);
+  expectType<string>(event);
 }
 
 export function createErrorsEventTest() {
@@ -215,39 +148,12 @@ export function createErrorsEventTest() {
       identifier: "agent-identifier",
     },
   ]);
-  expectType<() => string>(event.toString);
-  expectType<string>(event.toString());
-
-  expectType<
-    {
-      type: "reference" | "function" | "agent";
-      code: string;
-      message: string;
-      identifier: string;
-    }[]
-  >(event.data);
-
-  expectType<"copilot_errors">(event.event);
+  expectType<string>(event);
 }
 
 export function createDoneEventTest() {
   const event = createDoneEvent();
-  expectType<() => string>(event.toString);
-  expectType<string>(event.toString());
-
-  expectType<{
-    choices: [
-      {
-        finish_reason: "stop";
-        delta: {
-          content: null;
-        };
-      },
-    ];
-  }>(event.data);
-
-  // @ts-expect-error - .event is required
-  event.event;
+  expectType<string>(event);
 }
 
 export function parseRequestBodyTest(body: string) {
@@ -312,7 +218,7 @@ export async function promptTest() {
   await prompt("What is the capital of France?", {
     token: "secret",
     request: {
-      fetch: () => {},
+      fetch: () => { },
     },
   });