Angular Universal

Rendering JavaScript on the Server

@MarkPieszak

Hey! I'm Mark Pieszak

* Founder of http:// DevHelp.Online
Development / Consulting / Training Firm

- Helping teams and companies achieve their
Angular / JavaScript / ASP.NET goals.

* Angular Universal team

- Working on improving Universal
& Angular-CLI & ASP.NET integration

Who is this guy?

Mark

Pie

Zack

Szak

Check us out online!
http://DevHelp.Online

Catch me Online!

Github
@MarkPieszak

Twitter

@MarkPieszak

Medium

@MarkPieszak

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http://www.DevHelp.Online
Consulting / Training / Workshops / Development

Story
Time...

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Make sure to push

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to not miss any Slides !

Brief History of the Web

Server-side
Rendered
Websites

The Server-Side

Rendered Web

(Which has improved immensely
since the following screenshots of course!)

aka: SSR

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The old Web

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The old Web

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The old Web

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Some things change...
Others stay the same

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What does SSR get Right?

Search Engine Optimization

- Since everything was Server-rendered,
SEO was never an "issue"...

- It was just something you
had to add in your code

Great for Static sites

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Many other things...

Where does SSR lack sometimes?

Overall "User-Experience"

- Full page-loads were needed to show new content
or during any user interaction

- More server requests because of this

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What did the Web do next?

Brief History of the Web

Server-side
Rendered
Websites

Single Page Applications

Single Page Applications

aka: Client-side rendering

( CSR )

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More or less...

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What does CSR get Right?

A great fully interactive & rich user experience

Quick page transitions

Great for web applications

Overall we get that nice
"Perception"
that things are -happening-

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Where does CSR fall short?

No Search-engine optimization (at least not easily)

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Where does CSR fall short?

Longer initial load time

- Waiting for assets to download

- Code needs to run

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Where do we go from here?

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SSR

CSR

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SSR

CSR

SEO ✔
Faster initial paint ✔
Social Media Link Previews ✔
	Great user experience ✔
	Fully interactive ✔

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Can we get the best of both worlds?

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SSR

CSR

The Birth of
"Isomorphic"
JavaScript

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Brief History of the Web

Server-side
Rendered
Websites

Single Page Applications

"Isomorphic" JavaScript

What is Isomorphic JavaScript?

JavaScript
Application
<code />

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Same JavaScript Code running
on the Server

Same JavaScript Code running
on the Browser

This was me...

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Serialize the application
to a String "<html><head>..."

Your Applications JS code gets downloaded and begins to Bootstrap

( In the background ...)

JavaScript
Application
<code />

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serve it to the browser

Application finishes bootstrapping

Now we have a
- fully functioning -
Single Page Application

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Angular Universal

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Community-driven project originally
Originally created by:

Patrick Stapleton (PatrickJS)
Co-Founder of OneSpeed.io

Jeff Whelpley
CTO GetHuman

Rest of the Universal Team:

Mark Pieszak (me)
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Jason Jean
Forbes

Jeff Cross
Nrwl.io

Wassim Chegham
SFEIR

Alex Rickabaugh
Angular Core Team

Vikram Subramanian
Angular Core Team

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Moved from a separate repo to
inside Angular Core in 2017

Angular Universal

@angular/
platform-server

renderModuleFactory()

Angular Code bundles
"Bootstraps"
platformBrowser()

( In the background ...)

Angular
Application
<code />

Node Server

App to a String

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Angular
Application
<code />

When it finishes Bootstrapping, it replaces existing HTML "App" with Client-side rendered SPA version.

Boom! We have a normal Angular application

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Angular-CLI Integration

git clone http://www.github.com/angular/universal-starter

cd universal-starter

npm i 
// or yarn install

// To run Dynamic universal rendering
npm run build:ssr && npm run serve:ssr
// Open localhost:4000

// To run Static "prerendering"
npm run build:prerender && npm run serve:prerender
// Open http://127.0.0.1:8080

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- Start Here -
Working Example

http://www.github.com/angular/universal-starter

Angular-CLI Integration

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Have an existing CLI Application
you want to make Universal?

https://github.com/angular/angular-cli/wiki/stories-universal-rendering

Read the CLI Wiki story on Universal

How does Universal work?

Essentially lots of Dependency Injection

Possible because of Angular's

Compiler & Renderer not being tied to the Browser.

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How does Universal work?

Dependency Injection Mania

Provide	Use
RenderFactory2	ServerRenderFactory2
BrowserXHR	ServerXHR (Zone wrapped)
DOCUMENT	Domino
PlatformLocation	ServerPlatformLocation
StylesHost	ServerStylesHost

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Use these instead

How does Universal work?

Angular App

main.ts

main.server.ts

platformBrowser()

platformServer()

app.module.ts

app.server.module.ts

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How does Universal work?

Angular App

BrowserModule

imports AppModule

imports ServerModule

app.module.ts

app.server.module.ts

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How does Universal work?

@NgModule({
  exports: [BrowserModule],
  imports: [HttpModule, HttpClientModule, NoopAnimationsModule],
  providers: [
    SERVER_RENDER_PROVIDERS,
    SERVER_HTTP_PROVIDERS,
    {provide: Testability, useValue: null},
  ],
})

export class ServerModule { } // <--

ServerModule imports all the Dependency Injection -magic-

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Static vs Dynamic Rendering?

Static prerendering is done at BUILD-time
- Great for Static sites
- Each route will have its content pre-rendered into an .html

file

- Simply `serve` up the dist/browser folder to your server.

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/ dist /

    / browser / 
    
        index.html
        about.html
        contactus.html
        // ... etc ...

Static vs Dynamic Rendering?

Dynamic SSR is done at RUN-time
- This is more typical, dynamic sites where data is Http based

and data is constantly changing.
- Each route will render at run-time when requested and is served to the client.

- You must deploy the Node server

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/ dist /

    / browser /
        index.html
        // static assets
 
    / server / 
        // our server "universal" bundle, etc...

    // ** Our Node Express server we need to fire up **
    server.js

Node server time

import { AppServerModuleNgFactory } from './PATH/TO/server.bundle';
import { renderModuleFactory } from '@angular/platform-server';
import * from 'fs';

// Express server
const app = express();

app.get('*', (req, res) => {

    renderModuleFactory(AppServerModuleNgFactory, {
        extraProviders: [
            {
                provide: INITIAL_CONFIG,
                useValue: {
                  document: fs.readFileSync('dist/browser/index.html').toString(),
                  url: req.originalUrl
                }
            },
            // other providers you want to pass in
        ]
    }).then(html => {
        res.send(html);

    }).catch(error => { // errors });
});

app.listen(4000, () => {
  console.log(`Node Express server listening on http://localhost:${PORT}`);
});

This is NOT a working example - just conceptual

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For every Request

Serialize our Angular AoT'd Angular NgModule

Our index.html

Current URL

Send the resulting <html>
to the Browser!

Node server time

You can use renderModuleFactory() manually,
but I'd recommend just using the expressEngine.

http://www.github.com/angular/universal

Additional Universal libraries found in the npm namespace @nguniversal

More add-ons, coming soon!

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@nguniversal express-engine


import { ngExpressEngine } from '@nguniversal/express-engine';
import { provideModuleMap } from '@nguniversal/module-map-ngfactory-loader';

// Our Universal express-engine (github.com/angular/universal)
app.engine('html', ngExpressEngine({
    bootstrap: AppServerModuleNgFactory,
    providers: [
        provideModuleMap(LAZY_MODULE_MAP)
    ]
}));

app.set('view engine', 'html');

app.get('*', (req: Request, res: Response) => {
  res.render('index', {
    req,
    res
  });
});

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Notice Request/Response are passed in to the Engine which handles creating the InjectionTokens and passes them into Angular,
now you can use them within your Angular App!

import { Injector } from '@angular/core';

import { Request, Response } from 'express';
import { REQUEST, RESPONSE } from '@nguniversal/express-engine/tokens'; // <--

export SomeComponent {

    private request: Request;
    private response: Response;

    constructor(
        private injector: Injector
    ) { 
        this.request = this.injector.get(REQUEST);
        this.response = this.injector.get(RESPONSE);

        // cookies / headers / anything from our original Node Request
        // same with Response
    }
}

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Request/Response inside your Angular App

@nguniversal express-engine

Grab the Request/Response using the Injector

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Common SSR Gotchas

Server-side Render

Client-side Render

Renders entire App

Renders entire App
Again

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Common SSR Gotchas

Server-side Render

Client-side Render

Http call made here

Http call will be triggered -again-

Template "flickers" when Data goes blank then re-appears

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Common SSR Gotchas

Server-side Render

Client-side Render

Component "B" uses
"window" or "document"

"window/document" exists in the Browser-world

How does Node handle it?

Throws error, server stops.

No Bueno...

How can we handle these common SSR issues in our Angular Universal Apps?

New to Angular 5.0

- Upcoming in Angular 5.0 is the new TransferState

- Use this so Http calls don't get hit TWICE
Once during SSR, and again during CSR.

- Use TransferHttpCacheModule to have all GET HttpClient requests automatically transferred and re-used!

import { BrowserTransferStateModule } from '@angular/platform-browser';
import { TransferHttpCacheModule } from '@nguniversal/common';

imports: [
  // ...
  HttpClientModule,
  TransferHttpCacheModule, // <-- automatically caches HttpClient GET requests
  BrowserTransferStateModule // <--
]

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import { ServerTransferStateModule } from '@angular/platform-server';
imports: [ 
  // ... 
  ServerTransferStateModule // <--
]

Browser (app.module.ts)

Server (app.server.module.ts)

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Now with HttpTransferCache

Server-side Render

Client-side Render

Http call made here

Http call re-used

Data sent down with html and re-used
when CSR calls the same Http call

Other Universal "Gotchas"

- Never touch the "window"
- If you must, create a WindowService and use
Depenency Injection to provide different versions

@Injectable()
export class WindowService {
  // Some typical window use-cases
  public navigator: any = {};
  public location: any = {};
  public alert(msg: string) { return; }
  public confirm(msg: string) { return; }
  public setTimeout(handler: (...args: any[]) => void, timeout?: number): number { return 0; }
  public clearTimeout(timeoutId: number): void { }
  public setInterval(handler: (...args: any[]) => void, ms?: number, ...args: any[]): number { return 0; }
  public clearInterval(intervalId: number): void { }
  public ga(command: string | Function, params?: any, extra?: any): void { }
  // ...
}

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export function win () {
  return typeof window !== 'undefined' ? window : {};
}

// NgModule providers[]
{ 
   provide: WindowService, 
   useFactory: (win) // ^ above
}

// app.server.module.ts NgModule providers[]
{ provide: WindowService, useClass: WindowService },

Browser (app.module.ts)

Server (app.server.module.ts)

Other Universal "Gotchas"

- Never touch the "window"
- Also, try to wrap these things and ONLY do them if you're in the Browser Platform.

import { OnInit, PLATFORM_ID } from '@angular/core';
import { isPlatformBrowser, isPlatformServer } from '@angular/common';

export class SomeComponent implements OnInit {

  private isBrowser: boolean = isPlatformBrowser(this.platformId);

  constructor(
    private window: WindowService,
    @Inject(PLATFORM_ID) private platformId: Object
  ) { }

  ngOnInit() {

    if (this.isBrowser) { 
      (<any>this.windowService).$('body')... // something crazy involving the window
    }

  }
}

Protip: Use isPlatformBrowser() as much as possible!

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Other Universal "Gotchas"

- If you -must- use document, grab it from platform-browser


import { DOCUMENT } from '@angular/common';

constructor(@Inject(DOCUMENT) private document) { 
  this.document.querySelector('#test') // do something
}

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Using Window/Document

Server-side Render

Client-side Render

Component "B" uses
"window" or "document"

"window/document" exists in the Browser-world

Because of Dependency Injection, window never used.

Node keeps running

Other Universal "Gotchas"

- Be careful with setTimeout & setInterval

import { PLATFORM_ID } from '@angular/core';
import { isPlatformBrowser, isPlatformServer } from '@angular/common';

export class SomeComponent {

  private isBrowser: boolean = isPlatformBrowser(this.platformId);

  constructor(
    private window: WindowService,
    @Inject(PLATFORM_ID) private platformId: Object
  ) { }

  ngOnInit() {
    if (this.isBrowser) { 
      setTimeout(() => { }, 1000);
    }

    // or you can use the WindowService you create
    if (this.isBrowser) { 
      (<any>this.windowService).setTimeout(() => { }, 1000);
    }
  }
}

They WILL delay your Server-render, as Zones will be waiting

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Want more?

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For more Gotchas and other tips & tricks
Visit the Universal repo:

http://www.github.com/Angular/Universal

... More documentation coming soon ...

In Conclusion

SSR can help you avoid the "Loading" splash screen
- Especially helpful on slower networks

On slower networks (3G / etc) you can get a faster initial paint and "perception" that the App's performance is much faster.
- Can be ~ 2-3x faster "initial paint"

You can finally get SEO & Social-Media Previews

Be mindful of browser-specific things you might be using in your code!
- Also make sure you choose 3rd party libraries carefully as well! For the same reason.

In Conclusion

We went from

To this:

As for the question of
"can we have the best of both worlds? "

Yes!

( with a little effort of course )

So ...

Thank You !

Follow me on Twitter
I'll post a link to the slides later

Github
@MarkPieszak

Twitter

@MarkPieszak

Medium

@MarkPieszak

DevHelp.Online

http://www.DevHelp.Online
Consulting / Training / Workshops / Development

Angular Universal

Hey! I'm Mark Pieszak

Who is this guy?

Catch me Online!

Story Time...

Brief History of the Web

The Server-Side

Rendered Web

The old Web

The old Web

The old Web

Some things change... Others stay the same

What does SSR get Right?

Where does SSR lack sometimes?

Brief History of the Web

Single Page Applications

aka: Client-side rendering

( CSR )

What does CSR get Right?

Where does CSR fall short?

Where does CSR fall short?

Where do we go from here?

SSR

CSR

SSR

CSR

Can we get the best of both worlds?

SSR

CSR

The Birth of "Isomorphic" JavaScript

Brief History of the Web

What is Isomorphic JavaScript?

Angular Universal

Angular-CLI Integration

Angular-CLI Integration

How does Universal work?

How does Universal work?

How does Universal work?

How does Universal work?

How does Universal work?

Static vs Dynamic Rendering?

Static vs Dynamic Rendering?

Node server time

Node server time

@nguniversal express-engine

@nguniversal express-engine

Common SSR Gotchas

Common SSR Gotchas

Common SSR Gotchas

How can we handle these common SSR issues in our Angular Universal Apps?

New to Angular 5.0

Now with HttpTransferCache

Other Universal "Gotchas"

Other Universal "Gotchas"

Other Universal "Gotchas"

Using Window/Document

Other Universal "Gotchas"

Want more?

In Conclusion

In Conclusion

As for the question of "can we have the best of both worlds? "

Yes!

Thank You !

Story
Time...

Some things change...
Others stay the same

The Birth of
"Isomorphic"
JavaScript

As for the question of
"can we have the best of both worlds? "