Category: Angular

Rendering cycle in Angular applications — browser, angular and zone.js interaction | Angular In Depth

Source: Rendering cycle in Angular applications — browser, angular and zone.js interaction | by Max Koretskyi | Angular In Depth | Jan, 2023 | Medium

Running Angular on an IIS web server

Step 1.
Build your angular application for “production”:
ng build –dist -> output entire site to root/dist folder copy that folder to your IIS website folder.

Step 2.
IIS uses a file called web.config to setup some configuration for a website.
Make sure you have something similar as below in a web.config file in the site root folder (a typical Angular config scenario):

<configuration>
  <system.webServer>
    <!-- These rewrite rules requires the IIS Rewrite module -->
    <rewrite>
      <rules>
        <!-- Support for Angular internal url routing system (routing module) -->
        <rule name="Angular routing" stopProcessing="true">
          <match url=".*" />
          <conditions logicalGrouping="MatchAll">
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
            <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
          </conditions>
          <action type="Rewrite" url="/" />
        </rule>
        <!-- Adds https scheme if missing for all URLs -->
        <rule name="FQDN to SSL" stopProcessing="true">
          <match url="^(.*)$" />
          <conditions>
            <add input="{HTTPS}" pattern="^OFF$" />
          </conditions>
          <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" />
        </rule>
      </rules>
    </rewrite>
    <!-- Mime type fix for woff2 font file type -->
    <staticContent>
      <remove fileExtension=".woff2" />
      <mimeMap fileExtension=".woff2" mimeType="font/woff2" />
    </staticContent>
  </system.webServer>

  <!-- Its okay to cache these static files, index.html will include cache busting paths for Angular js and css files. (when building with --dist param) -->
  <system.webServer>
    <caching enabled="true">
      <profiles>
        <add extension=".svg" policy="CacheUntilChange"/>
        <add extension=".ico" policy="CacheUntilChange"/>
        <add extension=".js" policy="CacheUntilChange"/>
        <add extension=".css" policy="CacheUntilChange"/>
      </profiles>
    </caching>
    <staticContent>
      <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="5.00:00:00" />
    </staticContent>
  </system.webServer>

  <!-- Make sure index.html is never cached -->
  <location path="index.html">
    <system.webServer>
      <staticContent>
        <clientCache cacheControlMode="DisableCache" cacheControlMaxAge="0.00:00:00" />
      </staticContent>
      <httpProtocol>
        <customHeaders>
          <add name="Cache-Control" value="no-cache, no-store, must-revalidate" />
          <add name="Pragma" value="no-cache" />
          <add name="Expires" value="-1" />
        </customHeaders>
      </httpProtocol>
    </system.webServer>
  </location>

</configuration>

 

Rxjs debugging subscribers

I wanted to see how many listeners there was for a certain subject, and where they reside in the source code.
Here is how in chrome devtools, put a breakpoint before the subjects .next() call. And inspect the subject:

observers array count = number of “listeners”
FunctionLocation = source code reference

(Context: Angular v11, rxjs)

Introduction to Angular Storybook – a tool for component UI development

Introduction to Storybook for Angular Storybook is a tool for UI development. It makes development faster and easier by isolating components. This allows you to work on one component at a time. You can develop entire UIs without needing to start up a complex dev stack, force certain data into your database, or navigate around your application.

Source: Introduction to Storybook

A simpler and smaller Angular starter project

A lot of complaints I heard when starting with Angular are about the sheer amount of files you get even on simple apps. When looking at the default starter template you get from Angular CLI’s ng new command, it’s true that it can be a bit overwhelming if you’re not used to it.

But it doesn’t have to always be that way. In this article, we’ll explore how we can create a smaller and simpler template that’s also easier to grasp for beginners, following the YAGNI principle.

(Angular version 14)
Source: A simpler and smaller Angular starter with ngLite – DEV Community

Use of Enums in Angular 8+ HTML template

in the TS

import { SomeEnum } from 'path-to-file';

public get SomeEnum() {
  return SomeEnum; 
}

in the HTML use

*ngIf="SomeEnum.someValue === 'abc'"

EDIT: Time goes by and we learn more as a developer, the approach I’m using right now doesn’t use the get method. Both solutions work, just choose the one you like the most.

in the TS

import { SomeEnum } from 'path-to-file';

export class ClassName {
  readonly SomeEnum = SomeEnum;
}

in the HTML use

*ngIf="SomeEnum.someValue === 'abc'"

From: Use of Enums in Angular 8 HTML template for *ngIf – Stack Overflow

Angular – How to force reload components with router navigation

(Tested in Angular 11 project)

One trick is to “double” navigate to force components to destroy and “update” their lifecycle.

E.g.:

/// Navigates to detail view
navigateToDetail(id: string) {

  // Navigates to start page first to "destroy" detail components if on same url
  this.router.navigate(['/']).then(() => {
    // Then navigates to desired url 
    let navigationExtras: NavigationExtras = { queryParams: { 'id': id} };
    this.router.navigate(['/view'], navigationExtras);
  });

}

I also added this to app-routing.module.ts: (not sure if it makes a difference with the above code)

@NgModule({
  imports: [RouterModule.forRoot(routes, {
    onSameUrlNavigation: 'reload',
  })],
  exports: [RouterModule],
})
export class AppRoutingModule {}

 

How to force Angular to reload components when navigating to same url

Tested in Angular 11:

In module config for route module:

@NgModule({
imports: [RouterModule.forRoot(routes, {
onSameUrlNavigation: 'reload',
})],
exports: [RouterModule],
})

Set onSameUrlNavigation to ‘reload’

Whan using router.navigate() force url to update by adding a unique query parameter:

let navigationExtras: NavigationExtras = {
  queryParams: {
     refreshToken: (new Date).getTime(); //pass a dummy parameter (i.e. the time in milliseconds since 1970 or use the npm uuid library), forces reload of unique url
  },
};
this.router.navigate(['/detail'], navigationExtras);

More info:

https://github.com/angular/angular/issues/13831

https://angular.io/api/router/Router

https://angular.io/api/router/RouteReuseStrategy

Angular 10+ Strict Mode

From Angular 10 (experimental) / 11 (default on create new app) you can get strict mode. In summary it reduces the bundle size (by 75%!) and increases the maintainability by disabling you to create objects of type ‘any’ (no untyped types)…

Angular 11+ CLI creates all new workspaces and projects with strict mode enabled.

Strict mode improves maintainability and helps you catch bugs ahead of time. Additionally, strict mode applications are easier to statically analyze and can help the ng update command refactor code more safely and precisely when you are updating to future versions of Angular.

Specifically, strict mode does the following:

More info:
https://angular.io/guide/strict-mode

Angular CLI Strict Mode. In Angular, we strongly believe in… | by Minko Gechev | Angular Blog