Gentleman-Skills angular-performance

Name: angular-performance
Author: Gentleman-Programming

install

source · Clone the upstream repo

git clone https://github.com/Gentleman-Programming/Gentleman-Skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/Gentleman-Programming/Gentleman-Skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/curated/angular/performance" ~/.claude/skills/gentleman-programming-gentleman-skills-angular-performance && rm -rf "$T"

manifest: curated/angular/performance/SKILL.md

source content

NgOptimizedImage (REQUIRED for images)

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

@Component({
  imports: [NgOptimizedImage],
  template: `
    <!-- LCP image: add priority -->
    <img ngSrc="hero.jpg" width="800" height="400" priority>
    
    <!-- Regular: lazy loaded by default -->
    <img ngSrc="thumb.jpg" width="200" height="200">
    
    <!-- Fill mode (parent needs position: relative) -->
    <img ngSrc="bg.jpg" fill>
    
    <!-- With placeholder -->
    <img ngSrc="photo.jpg" width="400" height="300" placeholder>
  `
})

Rules

ALWAYS set
```
width
```
and
```
height
```
(or
```
fill
```
)
Add
```
priority
```
to LCP (Largest Contentful Paint) image
Use
```
ngSrc
```
not
```
src
```
Parent of
```
fill
```
image must have
```
position: relative/fixed/absolute
```

@defer - Lazy Components

@defer (on viewport) {
  <heavy-component />
} @placeholder {
  <p>Placeholder shown immediately</p>
} @loading (minimum 200ms) {
  <spinner />
} @error {
  <p>Failed to load</p>
}

Triggers

Trigger	When to Use
`on viewport`	Below the fold content
`on interaction`	Load on click/focus/hover
`on idle`	Load when browser is idle
`on timer(500ms)`	Load after delay
`when condition`	Load when expression is true

<!-- Multiple triggers -->
@defer (on viewport; on interaction) {
  <comments />
}

<!-- Conditional -->
@defer (when showComments()) {
  <comments />
}

Lazy Routes

// Single component
{
  path: 'admin',
  loadComponent: () => import('./features/admin/admin').then(c => c.AdminComponent)
}

// Feature with child routes
{
  path: 'users',
  loadChildren: () => import('./features/users/routes').then(m => m.USERS_ROUTES)
}

SSR & Hydration

bootstrapApplication(AppComponent, {
  providers: [
    provideClientHydration()
  ]
});

Scenario	Use
SEO critical (blog, e-commerce)	SSR
Dashboard/Admin	CSR
Static marketing site	SSG/Prerender

Slow Computations

Solution	When
Optimize algorithm	First choice always
Pure pipes	Cache single result
Memoization	Cache multiple results
`computed()`	Derived signal state

NEVER trigger reflows/repaints in lifecycle hooks (

ngOnInit

ngAfterViewInit