tauri-plugins-workspace/plugins/websocket/guest-js/index.ts

// Copyright 2019-2023 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

declare global {
  interface Window {
    __TAURI_INVOKE__: <T>(cmd: string, args?: unknown) => Promise<T>;
    __TAURI__: {
      transformCallback: <T>(cb: (payload: T) => void) => number;
    };
  }
}

export interface MessageKind<T, D> {
  type: T;
  data: D;
}

export interface CloseFrame {
  code: number;
  reason: string;
}

export type Message =
  | MessageKind<"Text", string>
  | MessageKind<"Binary", number[]>
  | MessageKind<"Ping", number[]>
  | MessageKind<"Pong", number[]>
  | MessageKind<"Close", CloseFrame | null>;

export default class WebSocket {
  id: number;
  private readonly listeners: Array<(arg: Message) => void>;

  constructor(id: number, listeners: Array<(arg: Message) => void>) {
    this.id = id;
    this.listeners = listeners;
  }

  static async connect(url: string, options?: unknown): Promise<WebSocket> {
    const listeners: Array<(arg: Message) => void> = [];
    const handler = (message: Message): void => {
      listeners.forEach((l) => l(message));
    };

    return await window
      .__TAURI_INVOKE__<number>("plugin:websocket|connect", {
        url,
        callbackFunction: window.__TAURI__.transformCallback(handler),
        options,
      })
      .then((id) => new WebSocket(id, listeners));
  }

  addListener(cb: (arg: Message) => void): void {
    this.listeners.push(cb);
  }

  async send(message: Message | string | number[]): Promise<void> {
    let m: Message;
    if (typeof message === "string") {
      m = { type: "Text", data: message };
    } else if (typeof message === "object" && "type" in message) {
      m = message;
    } else if (Array.isArray(message)) {
      m = { type: "Binary", data: message };
    } else {
      throw new Error(
        "invalid `message` type, expected a `{ type: string, data: any }` object, a string or a numeric array"
      );
    }
    return await window.__TAURI_INVOKE__("plugin:websocket|send", {
      id: this.id,
      message: m,
    });
  }

  async disconnect(): Promise<void> {
    return await this.send({
      type: "Close",
      data: {
        code: 1000,
        reason: "Disconnected by client",
      },
    });
  }
}