chore(internal): cleanup event stream helpers (#950)

* [wip]: refactor

* a solution

* Bind this

* fix formatting

---------

Co-authored-by: Young-Jin Park <[email protected]>

Author: 2 people

src/lib/AbstractChatCompletionRunner.ts

@@ -8,7 +8,7 @@ import {
   type ChatCompletionCreateParams,
   type ChatCompletionTool,
 } from 'openai/resources/chat/completions';
-import { APIUserAbortError, OpenAIError } from 'openai/error';
+import { OpenAIError } from 'openai/error';
 import {
   type RunnableFunction,
   isRunnableFunctionWithParse,
@@ -20,75 +20,36 @@ import {
   ChatCompletionStreamingToolRunnerParams,
 } from './ChatCompletionStreamingRunner';
 import { isAssistantMessage, isFunctionMessage, isToolMessage } from './chatCompletionUtils';
+import { BaseEvents, EventStream } from './EventStream';
 
 const DEFAULT_MAX_CHAT_COMPLETIONS = 10;
 export interface RunnerOptions extends Core.RequestOptions {
   /** How many requests to make before canceling. Default 10. */
   maxChatCompletions?: number;
 }
 
-export abstract class AbstractChatCompletionRunner<
-  Events extends CustomEvents<any> = AbstractChatCompletionRunnerEvents,
-> {
-  controller: AbortController = new AbortController();
-
-  #connectedPromise: Promise<void>;
-  #resolveConnectedPromise: () => void = () => {};
-  #rejectConnectedPromise: (error: OpenAIError) => void = () => {};
-
-  #endPromise: Promise<void>;
-  #resolveEndPromise: () => void = () => {};
-  #rejectEndPromise: (error: OpenAIError) => void = () => {};
-
-  #listeners: { [Event in keyof Events]?: ListenersForEvent<Events, Event> } = {};
-
+export class AbstractChatCompletionRunner<
+  EventTypes extends AbstractChatCompletionRunnerEvents,
+> extends EventStream<EventTypes> {
   protected _chatCompletions: ChatCompletion[] = [];
   messages: ChatCompletionMessageParam[] = [];
 
-  #ended = false;
-  #errored = false;
-  #aborted = false;
-  #catchingPromiseCreated = false;
-
-  constructor() {
-    this.#connectedPromise = new Promise<void>((resolve, reject) => {
-      this.#resolveConnectedPromise = resolve;
-      this.#rejectConnectedPromise = reject;
-    });
-
-    this.#endPromise = new Promise<void>((resolve, reject) => {
-      this.#resolveEndPromise = resolve;
-      this.#rejectEndPromise = reject;
-    });
-
-    // Don't let these promises cause unhandled rejection errors.
-    // we will manually cause an unhandled rejection error later
-    // if the user hasn't registered any error listener or called
-    // any promise-returning method.
-    this.#connectedPromise.catch(() => {});
-    this.#endPromise.catch(() => {});
-  }
-
-  protected _run(executor: () => Promise<any>) {
-    // Unfortunately if we call `executor()` immediately we get runtime errors about
-    // references to `this` before the `super()` constructor call returns.
-    setTimeout(() => {
-      executor().then(() => {
-        this._emitFinal();
-        this._emit('end');
-      }, this.#handleError);
-    }, 0);
-  }
-
-  protected _addChatCompletion(chatCompletion: ChatCompletion): ChatCompletion {
+  protected _addChatCompletion(
+    this: AbstractChatCompletionRunner<AbstractChatCompletionRunnerEvents>,
+    chatCompletion: ChatCompletion,
+  ): ChatCompletion {
     this._chatCompletions.push(chatCompletion);
     this._emit('chatCompletion', chatCompletion);
     const message = chatCompletion.choices[0]?.message;
     if (message) this._addMessage(message as ChatCompletionMessageParam);
     return chatCompletion;
   }
 
-  protected _addMessage(message: ChatCompletionMessageParam, emit = true) {
+  protected _addMessage(
+    this: AbstractChatCompletionRunner<AbstractChatCompletionRunnerEvents>,
+    message: ChatCompletionMessageParam,
+    emit = true,
+  ) {
     if (!('content' in message)) message.content = null;
 
     this.messages.push(message);
@@ -110,99 +71,6 @@ export abstract class AbstractChatCompletionRunner<
     }
   }
 
-  protected _connected() {
-    if (this.ended) return;
-    this.#resolveConnectedPromise();
-    this._emit('connect');
-  }
-
-  get ended(): boolean {
-    return this.#ended;
-  }
-
-  get errored(): boolean {
-    return this.#errored;
-  }
-
-  get aborted(): boolean {
-    return this.#aborted;
-  }
-
-  abort() {
-    this.controller.abort();
-  }
-
-  /**
-   * Adds the listener function to the end of the listeners array for the event.
-   * No checks are made to see if the listener has already been added. Multiple calls passing
-   * the same combination of event and listener will result in the listener being added, and
-   * called, multiple times.
-   * @returns this ChatCompletionStream, so that calls can be chained
-   */
-  on<Event extends keyof Events>(event: Event, listener: ListenerForEvent<Events, Event>): this {
-    const listeners: ListenersForEvent<Events, Event> =
-      this.#listeners[event] || (this.#listeners[event] = []);
-    listeners.push({ listener });
-    return this;
-  }
-
-  /**
-   * Removes the specified listener from the listener array for the event.
-   * off() will remove, at most, one instance of a listener from the listener array. If any single
-   * listener has been added multiple times to the listener array for the specified event, then
-   * off() must be called multiple times to remove each instance.
-   * @returns this ChatCompletionStream, so that calls can be chained
-   */
-  off<Event extends keyof Events>(event: Event, listener: ListenerForEvent<Events, Event>): this {
-    const listeners = this.#listeners[event];
-    if (!listeners) return this;
-    const index = listeners.findIndex((l) => l.listener === listener);
-    if (index >= 0) listeners.splice(index, 1);
-    return this;
-  }
-
-  /**
-   * Adds a one-time listener function for the event. The next time the event is triggered,
-   * this listener is removed and then invoked.
-   * @returns this ChatCompletionStream, so that calls can be chained
-   */
-  once<Event extends keyof Events>(event: Event, listener: ListenerForEvent<Events, Event>): this {
-    const listeners: ListenersForEvent<Events, Event> =
-      this.#listeners[event] || (this.#listeners[event] = []);
-    listeners.push({ listener, once: true });
-    return this;
-  }
-
-  /**
-   * This is similar to `.once()`, but returns a Promise that resolves the next time
-   * the event is triggered, instead of calling a listener callback.
-   * @returns a Promise that resolves the next time given event is triggered,
-   * or rejects if an error is emitted.  (If you request the 'error' event,
-   * returns a promise that resolves with the error).
-   *
-   * Example:
-   *
-   *   const message = await stream.emitted('message') // rejects if the stream errors
-   */
-  emitted<Event extends keyof Events>(
-    event: Event,
-  ): Promise<
-    EventParameters<Events, Event> extends [infer Param] ? Param
-    : EventParameters<Events, Event> extends [] ? void
-    : EventParameters<Events, Event>
-  > {
-    return new Promise((resolve, reject) => {
-      this.#catchingPromiseCreated = true;
-      if (event !== 'error') this.once('error', reject);
-      this.once(event, resolve as any);
-    });
-  }
-
-  async done(): Promise<void> {
-    this.#catchingPromiseCreated = true;
-    await this.#endPromise;
-  }
-
   /**
    * @returns a promise that resolves with the final ChatCompletion, or rejects
    * if an error occurred or the stream ended prematurely without producing a ChatCompletion.
@@ -327,75 +195,7 @@ export abstract class AbstractChatCompletionRunner<
     return [...this._chatCompletions];
   }
 
-  #handleError = (error: unknown) => {
-    this.#errored = true;
-    if (error instanceof Error && error.name === 'AbortError') {
-      error = new APIUserAbortError();
-    }
-    if (error instanceof APIUserAbortError) {
-      this.#aborted = true;
-      return this._emit('abort', error);
-    }
-    if (error instanceof OpenAIError) {
-      return this._emit('error', error);
-    }
-    if (error instanceof Error) {
-      const openAIError: OpenAIError = new OpenAIError(error.message);
-      // @ts-ignore
-      openAIError.cause = error;
-      return this._emit('error', openAIError);
-    }
-    return this._emit('error', new OpenAIError(String(error)));
-  };
-
-  protected _emit<Event extends keyof Events>(event: Event, ...args: EventParameters<Events, Event>) {
-    // make sure we don't emit any events after end
-    if (this.#ended) {
-      return;
-    }
-
-    if (event === 'end') {
-      this.#ended = true;
-      this.#resolveEndPromise();
-    }
-
-    const listeners: ListenersForEvent<Events, Event> | undefined = this.#listeners[event];
-    if (listeners) {
-      this.#listeners[event] = listeners.filter((l) => !l.once) as any;
-      listeners.forEach(({ listener }: any) => listener(...args));
-    }
-
-    if (event === 'abort') {
-      const error = args[0] as APIUserAbortError;
-      if (!this.#catchingPromiseCreated && !listeners?.length) {
-        Promise.reject(error);
-      }
-      this.#rejectConnectedPromise(error);
-      this.#rejectEndPromise(error);
-      this._emit('end');
-      return;
-    }
-
-    if (event === 'error') {
-      // NOTE: _emit('error', error) should only be called from #handleError().
-
-      const error = args[0] as OpenAIError;
-      if (!this.#catchingPromiseCreated && !listeners?.length) {
-        // Trigger an unhandled rejection if the user hasn't registered any error handlers.
-        // If you are seeing stack traces here, make sure to handle errors via either:
-        // - runner.on('error', () => ...)
-        // - await runner.done()
-        // - await runner.finalChatCompletion()
-        // - etc.
-        Promise.reject(error);
-      }
-      this.#rejectConnectedPromise(error);
-      this.#rejectEndPromise(error);
-      this._emit('end');
-    }
-  }
-
-  protected _emitFinal() {
+  protected override _emitFinal(this: AbstractChatCompletionRunner<AbstractChatCompletionRunnerEvents>) {
     const completion = this._chatCompletions[this._chatCompletions.length - 1];
     if (completion) this._emit('finalChatCompletion', completion);
     const finalMessage = this.#getFinalMessage();
@@ -650,27 +450,7 @@ export abstract class AbstractChatCompletionRunner<
   }
 }
 
-type CustomEvents<Event extends string> = {
-  [k in Event]: k extends keyof AbstractChatCompletionRunnerEvents ? AbstractChatCompletionRunnerEvents[k]
-  : (...args: any[]) => void;
-};
-
-type ListenerForEvent<Events extends CustomEvents<any>, Event extends keyof Events> = Event extends (
-  keyof AbstractChatCompletionRunnerEvents
-) ?
-  AbstractChatCompletionRunnerEvents[Event]
-: Events[Event];
-
-type ListenersForEvent<Events extends CustomEvents<any>, Event extends keyof Events> = Array<{
-  listener: ListenerForEvent<Events, Event>;
-  once?: boolean;
-}>;
-type EventParameters<Events extends CustomEvents<any>, Event extends keyof Events> = Parameters<
-  ListenerForEvent<Events, Event>
->;
-
-export interface AbstractChatCompletionRunnerEvents {
-  connect: () => void;
+export interface AbstractChatCompletionRunnerEvents extends BaseEvents {
   functionCall: (functionCall: ChatCompletionMessage.FunctionCall) => void;
   message: (message: ChatCompletionMessageParam) => void;
   chatCompletion: (completion: ChatCompletion) => void;
@@ -680,8 +460,5 @@ export interface AbstractChatCompletionRunnerEvents {
   finalFunctionCall: (functionCall: ChatCompletionMessage.FunctionCall) => void;
   functionCallResult: (content: string) => void;
   finalFunctionCallResult: (content: string) => void;
-  error: (error: OpenAIError) => void;
-  abort: (error: APIUserAbortError) => void;
-  end: () => void;
   totalUsage: (usage: CompletionUsage) => void;
 }