get Azure graph token by custom authentication provider by client_id and client_secret

msGraph.ts

import { Client } from "@microsoft/microsoft-graph-client";
import { MyAuthenticationProvider } from "./MyAuthenticationProvider";

const clientOptions = {
  authProvider: new MyAuthenticationProvider(),
};
const client = Client.initWithMiddleware(clientOptions);

MyAuthenticationProvider.ts

import { AuthenticationProvider } from "@microsoft/microsoft-graph-client";
const axios = require("axios").default;
const qs = require("qs");
const msGraph_AuthUrl = process.env.msGraph_AuthUrl;
const msGraph_client_id = process.env.msGraph_client_id;
const msGraph_client_secret = process.env.msGraph_client_secret;
const msGraph_tenant_id = process.env.msGraph_tenant_id;
export class MyAuthenticationProvider implements AuthenticationProvider {
  /**
   * This method will get called before every request to the msgraph server
   * This should return a Promise that resolves to an accessToken (in case of success) or rejects with error (in case of failure)
   * Basically this method will contain the implementation for getting and refreshing accessTokens
   */
  public async getAccessToken(): Promise<string> {
    let data = qs.stringify({
      client_id: msGraph_client_id,
      client_secret: msGraph_client_secret,
      scope: "https://graph.microsoft.com/.default",
      grant_type: "client_credentials",
    });
    let config = {
      method: "post",
      url: `${msGraph_AuthUrl}/${msGraph_tenant_id}/oauth2/v2.0/token`,
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
      },
      data: data,
    };
    let response = await axios(config)
      .then(function (resp: any) {
        console.log("Token Received");
        return resp.data.access_token;
      })
      .catch(function (error: any) {
        console.log(error);
      });
    return response;
  }
}