How to properly import and use the MSAL (Microsoft Authentication Library for js) into a typescript react single page application?

Question

Problem

I can't seem to get the MSAL library to import properly into my typescript code. I'm using the MSAL for JS library (which is supposed to have typings) in a simple typescript/react project scaffolded using the create-react-app with react-typescript scripts. I'm new to typescript and not sure if I'm missing something obvious or if there is a problem with the MSAL package when using it with typescript projects.

Details:

1. I added the MSAL package from NPM using npm install --save msal.
2. I attempted to import the MSAL into my .ts using different forms of import {Msal} from 'msal';
3. This results in a typescript error Could not find a declaration file for module 'msal'. '<path>/node_modules/msal/out/msal.js' implicitly has an 'any' type.
4. Thinking that was odd, I looked at the the node_module/msal/out folder and saw a 'msal.d.ts' file, which is what I would expect.
5. When I look at the contents of the msal.d.ts file, I don't see any exports, which I would normally expect to see.
6. I tried install the declaration from @types using npm install --save-dev @types/msal, but it doesn't exist.
7. I also tried importing it into my file using let Msal = require('Msal');, but get an error that the Msal.UserAgentApplication isn't a constructor.
8. I didn't have much luck trying to use the /// reference directive and adding a script tag to the main index.html. This also doesn't feel like the right way to solve the problem.

ExampleMsal.ts

import { observable, action, computed } from 'mobx';
import * as Msal from 'msal'; // <-- This line gives the error

class ExampleMsal{
    @observable 
    private _isLoggedIn: boolean;

    constructor() {
        this._isLoggedIn = false;
    }

    @computed 
    get isLoggedIn(): boolean {
        return this._isLoggedIn;
    }

    @action 
    signIn() {

        let userAgentApplication = new Msal.UserAgentApplication('<client-id>', null, 
        function (errorDes: string, token: string, error: string, tokenType: string) {
            // this callback is called after loginRedirect OR acquireTokenRedirect 
            // (not used for loginPopup/aquireTokenPopup)
        }
        );

        userAgentApplication.loginPopup(['user.read']).then(function(token: string) {
            let user = userAgentApplication.getUser();
            if (user) {
                // signin successful
                alert('success');
            } else {
                // signin failure
                alert('fail');
            }
        }, function (error: string) {
            // handle error
            alert('Error' + error);
        });        
        this._isLoggedIn = true;
    }

    @action 
    signOut() {
        this._isLoggedIn = false;
    }
}

export default ExampleMsal;

tsconfig.json

{
  "compilerOptions": {
    "outDir": "build/dist",
    "module": "commonjs",
    "target": "es5",
    "lib": ["es6", "dom"],
    "sourceMap": true,
    "allowJs": true,
    "jsx": "react",
    "moduleResolution": "node",
    "rootDir": "src",
    "forceConsistentCasingInFileNames": true,
    "noImplicitReturns": true,
    "noImplicitThis": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "suppressImplicitAnyIndexErrors": true,
    "noUnusedLocals": true,
    "experimentalDecorators": true
  },
  "exclude": [
    "node_modules",
    "build",
    "scripts",
    "acceptance-tests",
    "webpack",
    "jest",
    "src/setupTests.ts"
  ],
  "types": [
    "typePatches"
  ]
}

Answer 1

It looks like the latest version of MSAL.js does have a CommonJS export. You can now just do the following in TypeScript (tested with version 2.3.3 of TypeScript and 0.1.3 of MSAL.js):

import * as Msal from 'msal';

Now in your .ts (or in my case .tsx file) you can, for instance, setup a click event handler and create a UserAgentApplication object:

// In you class somewhere
private userAgentApplication: any = undefined;

// The login button click handler
handleLoginClick = (event: any): void => {
    if (!this.userAgentApplication) {
        this.userAgentApplication = new Msal.UserAgentApplication(
            'clientID string', 'authority string or empty', this.authCallback, { cacheLocation: 'localStorage'});
    }
    // Other login stuff...
}

// In React render()
public render() {
    return (
        <Button
            bsStyle="warning"
            type="button"
            onClick={(e) => this.handleLoginClick(e)}
        >
        Log in
        </Button>
    );
}