Error Handling

This guide covers the TResult error handling pattern, including type structure, usage, error code design, and best practices.

TResult Design Philosophy

All async public methods in the SDK return TResult<T> — never throw:

• Expected errors are expressed via result.ok === false
• Localized messages via result.message can be shown directly to users
• Debug info via result.detail is provided for developers
• Error codes via result.code support programmatic handling

TResult<T> Type Structure

// Success result
interface TResultOk<T> {
  ok: true;
  data: T;           // Return data on success
  code: 0;
  message: '';
  detail: '';
}

// Failure result
interface TResultFail {
  ok: false;
  data: undefined;
  code: TResultCode; // Error code enum
  message: string;   // Localized message (show directly to users)
  detail: string;    // English debug info (for developer troubleshooting)
}

// Union type
type TResult<T = void> = TResultOk<T> | TResultFail;

Basic Usage

// Standard usage: check ok before accessing data
const result = await classroom.joinClass(params);
if (!result.ok) {
  showToast(result.message);           // Show to user
  console.error(result.detail);        // Developer debug
  console.error('Error code:', result.code); // Programmatic handling
  return;
}
// Success branch — TypeScript auto-narrows type, result.data safely accessible
console.log('Joined successfully');

Methods with Return Data

const result = await classroom.getCameraList();
if (result.ok) {
  // result.data is typed as TDeviceInfo[]
  const cameras = result.data;
  cameras.forEach(cam => console.log(cam.deviceId, cam.label));
}

TResultCode Segment Design

Error codes are segmented by module for quick problem source identification:

Range	Module	Description
1000 ~ 1999	Framework	Initialization, module registration, lifecycle
10000 ~ 10999	API	Network requests, server-returned errors
20000 ~ 20999	RTC	Audio/video (devices, publishing, subscribing)
30000 ~ 30999	IM	Instant messaging (connection, send, receive)
40000 ~ 40999	Board	Whiteboard (initialization, rendering, sync)

Common Error Codes

import { TResultCode } from '@tencent-classroom/sdk';

const result = await classroom.startCamera(element);
if (!result.ok) {
  switch (result.code) {
    case TResultCode.NOT_INITIALIZED:
      console.error('SDK not yet initialized');
      break;
    case TResultCode.DEVICE_NOT_FOUND:
      console.error('Camera device not found');
      break;
    case TResultCode.PERMISSION_DENIED:
      console.error('Camera permission not granted');
      break;
    default:
      console.error('Unknown error:', result.message);
  }
}

Unified Error Channel

The SDK provides a unified error event where all module runtime errors are collected:

import { TEvent } from '@tencent-classroom/sdk';

classroom.on(TEvent.ERROR, ({ module, code, message, detail }) => {
  console.error(`[${module}] ${code}: ${message}`);
  // Report to monitoring system
  reportError({ module, code, message, detail });
});

classroom.on(TEvent.WARN, ({ module, message }) => {
  console.warn(`[${module}] ${message}`);
});

Related APIs

• Enums & Types Reference — Complete TResultCode list
• Lifecycle API — init / joinClass methods