How to use the ms-rest.TokenCredentials function in ms-rest

constructor(application: LuisApplication, options?: LuisPredictionOptions, includeApiResults?: boolean) {
        this.application = application;
        this.options = {
            includeAllIntents: false,
            includeInstanceData: true,
            log: true,
            spellCheck: false,
            staging: false, ...options
        };
        this.includeApiResults = !!includeApiResults;

        // Create client
        const creds: msRest.TokenCredentials = new msRest.TokenCredentials(application.endpointKey);
        const baseUri: string = this.application.endpoint || 'https://westus.api.cognitive.microsoft.com';
        this.luisClient = new LuisClient(creds, baseUri);
    }

_setCredentials: function() {
    if (!this.isPlayback) {
      if (process.env['SKIP_CREDENTIAL_CHECK']) {
        let token = process.env['AZURE_ACCESS_TOKEN'] || 'token';
        this.credentials = new msRest.TokenCredentials('token');
      } else if ((process.env['AZURE_PASSWORD'] && process.env['APPLICATION_SECRET']) ||
        (!process.env['AZURE_PASSWORD'] && !process.env['APPLICATION_SECRET'])) {
        throw new Error('You must either set the envt. variables \'AZURE_USERNAME\' ' +
          'and \'AZURE_PASSWORD\' for running tests as a user or set the ' +
          'envt. variable \'CLIENT_ID\' and \'APPLICATION_SECRET\' ' +
          'for running tests as a service-principal, but not both.');
      }

      if (process.env['AZURE_PASSWORD']) {
        this.credentials = this._createUserCredentials();
      } else if (process.env['APPLICATION_SECRET']) {
        this.credentials = this._createApplicationCredentials();
      }
    } else {
      //The type of credential object does not matter in playback mode as authentication
      //header is not recorded. Hence we always default to UsertokenCredentials.

var verifyAadAuth = function(token, callback) {
        var tokenCreds = new msRest.TokenCredentials(token, 'Bearer');
        aadClient = new BatchServiceClient(tokenCreds, process.env['AZURE_BATCH_ENDPOINT']);
        aadClient.account.listSupportedImages(function (err, result, request, response) {
          should.not.exist(err);
          should.exist(result);
          result.length.should.be.above(0);
          response.statusCode.should.equal(200);
          should.exist(request.headers.authorization);
          request.headers.authorization.should.equal('Bearer ' + token);
          callback();
        });
      };

program.on('--help', function () {
        console.log('  Examples:');
        console.log('');
        console.log('    $ powerbi create-workspace -c  -k  -n ');
    });

    program.parse(process.argv);

    let settings = config.merge(program);

    if (!(settings.collection && settings.accessKey)) {
        program.help();
    } else {
        try {
            let credentials = new msrest.TokenCredentials(settings.accessKey, 'AppKey');
            let client = new powerbi.PowerBIClient(credentials, settings.baseUri, null);
            let workspaceRequest : powerbi.CreateWorkspaceRequest = {
                name: settings.newName,
            };
            let options = { workspaceRequest }

            client.workspaces.postWorkspace(settings.collection, options, (err, result) => {
                if (err) {
                    return cli.error(err);
                }

                cli.print('Workspace created: %s', result.workspaceId);
            });
        } catch (err) {
            cli.error(err);
        }

'use strict';

import should = require('should');

import http = require('http');
import assert = require('assert');
import * as msRest from 'ms-rest';
import fs = require('fs');

import stream = require('stream');

import validationClient = require('../Expected/AcceptanceTests/Validation/autoRestValidationTest');

var dummyToken = 'dummy12321343423';
var credentials = new msRest.TokenCredentials(dummyToken);
var clientOptions: msRest.ServiceClientOptions = {};
var baseUri = 'http://localhost:3000';
describe('nodejs', function () {
  describe('Swagger BAT Validation', function () {
    var testClient = new validationClient("abc123", "12-34-5678", baseUri, clientOptions);
    describe('Of Method Parameters', function () {
      it('should test the minimum length constraint on resourceGroupName', function (done) {
        testClient.validationOfMethodParameters("1", 100, function (err, result) {
          should.exist(err);
          err.should.match(/.*resourceGroupName.*constraint.*MinLength.*3/ig);
          done();
        });
      });

      it('should test the maximum length constraint on resourceGroupName', function (done) {
        testClient.validationOfMethodParameters("1234567890A", 100, function (err, result) {

.option('-b --baseUri [baseUri]', 'The base uri to connect to');

    program.on('--help', function () {
        console.log('  Examples:');
        console.log('');
        console.log('    $ powerbi get-workspaces -c  -k ');
    });

    program.parse(process.argv);
    let settings = config.merge(program);

    if (!(settings.collection && settings.accessKey)) {
        program.help();
    } else {
        try {
            let credentials = new msrest.TokenCredentials(settings.accessKey, 'AppKey');
            let client = new powerbi.PowerBIClient(credentials, settings.baseUri, null);

            client.workspaces.getWorkspacesByCollectionName(settings.collection, (err, result) => {
                if (err) {
                    return cli.error(err);
                }
                
                let workspaces = result.value;

                if (workspaces.length == 0) {
                    return cli.warn('No workspaces found within collection: %s', settings.collection);
                }

                cli.print("================================================");
                cli.print('Gettings workspaces for Collection: %s', settings.collection);
                cli.print("================================================");

program.on('--help', function () {
        console.log('  Examples:');
        console.log('');
        console.log('    $ powerbi import -c  -k  -w  -f  -n ');
    });

    program.parse(process.argv);
    let settings = config.merge(program);

    if (!(settings.collection && settings.workspace && settings.accessKey && settings.displayName && settings.file)) {
        program.help();
    } else {
        try {
            let options: powerbi.ImportFileOptions = {};
            let credentials = new msrest.TokenCredentials(settings.accessKey, 'AppKey');
            let client = new powerbi.PowerBIClient(credentials, settings.baseUri, null);

            if (!_.isUndefined(settings.overwrite) && settings.overwrite) {
                options.nameConflict = 'Overwrite';
            }

            options.datasetDisplayName = settings.displayName;

            if (!fs.existsSync(settings.file)) {
                throw new Error(util.format('File "%s" not found', settings.file));
            }

            cli.print('Importing %s to workspace: %s', settings.file, settings.workspace);

            client.imports.uploadFile(settings.collection, settings.workspace, settings.file, options, (err, result, request, response) => {
                if (err) {

export async function functionsAdminRequest(client: SiteClient, urlPath: string): Promise {
    const adminKey: string = await client.getFunctionsAdminToken();
    const url: string = `${client.defaultHostUrl}/admin/${urlPath}`;
    const request: requestUtils.Request = await requestUtils.getDefaultRequest(url, new TokenCredentials(adminKey));
    return await requestUtils.sendRequest(request);
}

            this.credentials = (this.tokens || []).reduce((credentials, token) => Object.assign(credentials, { [token._authority]: new TokenCredentials(token.accessToken) }), {});
        }