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How I Would Start A New Angular Project
Angular: A good choice for large-scale enterprise
applications
How I Would Start A New
Angular Project
Munich Frontend Developers Meetup
21.11.2019
Hi, I‘m Michael Hoffmann
Angular CLI
We can do better…
Agenda
Nx (Monorepo)
Domain Driven Design (DDD)
OnPush
Useful Tools & Tips
Nx from Nrwl for Monorepos
DEVELOP LIKE
Not just for BIG projects
MONOREPO? WHY?
One Repo
Nx Libs & Apps
/LIBS /APPS
TypeScript
models
UI component
library
NestJS backend
Angular frontend
React frontend
Basic Nx Fullstack Workspace
Monorepos are slow
Build & Test Changesnpm run dep-graph npm run dep-graph
Run only changed code
BENEFITS OF USING NX
• Build Full-Stack Applications
• Develop like Google
• Seamlessly use modern tools like Prettier, Cypress, Jest, Nest
Domain Driven Design (DDD)
How I Would Start A New Angular Project
BENEFITS OF USING DDD
• Scalable architecture
• Ubiquitous Language
• Better code with less duplication
• And more…
Reading
Recommendation
Free eBook from
Manfred Steyer:
https://leanpub.com/en
terprise-angular
Tracker Domain
ErrorHandler, GoogleAnalytics, LoggerService
Sentry: Error Tracking
LoggerService
Global Error Handler Service
BENEFITS OF USING TRACKER DOMAIN
• Be able to see errors before the user reports them
• Be able to analzye how an error happened
How I Would Start A New Angular Project
Jest vs. Karma/jasmine
Why not Karma/jasmine?
• Slow build times (especially initially)
• Slow test execution (especially in larger projects)
• Recompiling does not work reliably
• HTML reporter like karma-jasmine-html-reporter tend to be buggy
Why Jest?
• Easy setup (especially using Nx)
• Very fast (parallelization, run slowest tests first)
• Similar syntax as jasmine
• Good mocking support
• Provides snapshot testing
Test Tips
• Consider using Spectator instead of the TestBed API of Angular.
• Consider using Jest instead of Karma/Jasmine (Migration is quite easy)
• Consider using ng-mocks to mock your component, directives, services,
pipes and more. Your unit tests should be pure and therefore isolated.
• Test your component from the DOM and not the class, you should think
in user events instead of methods.
Cypress vs. Protractor
Cypress vs. Protractor
Cypress
• Not based on Selenium
• executes in the browser and in
the same run loop as the
device under test
• No cross-browser testing
• Can only be written in JS
• no cross-browser support
Protractor
• Based on Selenium which
• is the industry standard
• works across OS & programming
languages
• supports Cross-browser testing
(even IE)
• Main problem: timing
BENEFITS OF USING BETTER TESTING TOOLS
• Writing tests makes more fun
• Code is more readable
• Tests run faster
OnPush
Why OnPush? PERFORMANCE!
CD
CD
CD CD
CD
CD CD
ChangeDetectionStrategy. Default
CD
CD
CD CD
CD
CD CD
(EVENT)
ChangeDetectionStrategy. Default
CD
CD
CD
CD
CD CD CD
ChangeDetectionStrategy.Default
OnPush
CD
OnPush
OnPush OnPush
CD
CD CD
ChangeDetectionStrategy.OnPush
CD
OnPush
OnPush OnPush
CD
CD CD
(EVENT)
ChangeDetectionStrategy.OnPush
CD
OnPush
OnPush OnPush
CD
CD CD
ChangeDetectionStrategy.OnPush
More about Change Detection:
BENEFITS OF USING ONPUSH
• Better application performance
More Tools & Tips
Compodoc: Docs Generator
Strict TypeScript
TypeScript: strictNullChecks
…
…
undefined
11
undefined
NaN
null
33
number
number
undefined null
NaN
11
33
strictNullChecks
null
strictNullChecks
tsconfig.json
Internationalization (i18n)
Internationalization (i18n)
• Store translations in separate files and do not hardcode them in your
components
• Be prepared for multiple languages and dynamic language switches
Angular  use ngx-translate
Building Complex Components
• Use Angular CDK which provides a set of tools that implement common
interaction patterns whilst being unopinionated about their
presentation
• If you build your component also take a look at existing open-source
Angular libraries like Angular Material. There you can see how
components are written the “Angular way”.
• You can also look for existing Angular components in npm, therefore I
can recommend taking a look at curated component lists like Awesome
Angular Components or Awesome Angular.
UI Component
Library
• Put dumb components in
a UI component library
• Use something like
StoryBook to visualize
your components
Augury Browser Dev Tool
Prettier: Opinionated Code Formatter
What is Prettier?
• An opinionated code formatter
• Supports many languages
• Integrates with most editors
• Has few options
Why Prettier?
• You press save and code is
formatted
• No need to discuss style in
code review
• Saves you time and energy
• And more
Misc
• State management: Start with simple state using a service, use NgRx if state
becomes complex
• Use Husky, to check if commit message has the correct format, code is
formatted, linter has no errors and maybe also run unit tests before you push
your code.
• Lazy load all your modules. This way you can split your application in
multiple smaller bundles which are only loaded if necessary.
Corresponding Blog Post
mokkapps
Steps to your next successful Angular project
• Use Nx
• Use DDD
• Implement Error Handling &
Tracking
• Prepare for i18n
• Use available tools

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How I Would Start A New Angular Project

Notas do Editor

  1. Opiniated Release cycles & LTS DI, Forms, Router, TS, RxJS included
  2. Nx is an easy to use version of the powerful monorepo tools used at companies like Google
  3. Shared package.json Multiple technologies
  4. Build a graph which will never be out of sync! An Nx workspace can contain dozens or hundreds of applications and libraries. As a codebase grows, it can be difficult to understand how they depend on each other and the implications of making a particular change.
  5. Free for personal projects and early-stage applications View actual code in stack traces for over 32 languages and frameworks. stack traces Backend & frontend error tracking Trail of events by using breadcrumbs Version changes
  6. Snapshot testing is great. It lets you capture a string that represents your rendered component and store it in a file. Then you can compare it later to ensure that the UI didn't change
  7. Selenium executes in a process outside of the browser or device we are testing Cypress executes in the browser and in the same run loop as the device under test.
  8. supports all major APIs of Angular Open-source and on npm No server needed, no sources uploaded online Search engine 7 themes & responsive
  9. Angular CDK Angular Material code snippets GitHub curated component collections
  10. When an array changes, Angular re-renders the whole DOM tree. But if you use trackBy, Angular will know which element has changed and will only make DOM changes for that particular element.
  11. NgRX: you build an application with a lot of user interactions and multiple data sources, when managing state in services are no longer sufficient. Lazy load: reduce the size of the application to be loaded improve the application boot time by not loading the modules that are not used.