posttoteams.ts

const _postToTeams = async () => {

  const idToken = await microsoftTeams.authentication.getAuthToken();

  const teamsContext = await microsoftTeams.app.getContext();

  const teamId = teamsContext.team?.groupId;
  const channelId = teamsContext.channel?.id;
  const message = "This message will be posted to Teams using Microsoft Graph";

  await fetch(`/PostToTeams?teamId=${teamId}&channelId=${channelId}&message=${message}`, {
      method: 'POST',
      headers: {
          'Accept': 'application/json',
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${idToken}`
      }
  });
}