Creating components with CLI in Angular - Performance Optimization Steps

Performance: Creating components with CLI

MEDIUM IMPACT

This affects initial page load speed and bundle size by controlling how components are generated and included in the app.

Generating Angular components for a project

Angular

ng generate component my-component --skip-tests --inline-style --inline-template

Generates only essential code with inline styles and templates, skipping test files to reduce bundle size and build time.

📈 Performance Gainsaves ~3-5kb per component, reduces build time by avoiding extra files

Generating Angular components for a project

Angular

ng generate component my-component

Generates all default files including CSS, HTML, and test files even if not needed, increasing bundle size and build time.

📉 Performance Costadds ~3-5kb per unused file, slightly increases build time

Performance Comparison

Pattern	DOM Operations	Reflows	Paint Cost	Verdict
Default CLI component generation	Moderate (extra files increase DOM complexity)	Multiple reflows if many CSS files	Higher paint cost due to separate CSS	[X] Bad
CLI component with inline styles/templates and no tests	Lower (fewer files, simpler DOM)	Single reflow	Lower paint cost with inline styles	[OK] Good

Rendering Pipeline

Component creation affects the bundle size and code complexity, which impacts the browser's parsing and rendering speed during the critical rendering path.

→Parsing

→Style Calculation

→Layout

→Paint

⚠️ BottleneckParsing and Style Calculation due to larger bundles and more CSS files

Core Web Vital Affected

LCP

This affects initial page load speed and bundle size by controlling how components are generated and included in the app.

Optimization Tips

1Use Angular CLI flags like --inline-style and --inline-template to reduce file count and bundle size.

2Skip generating test files if not needed to save build time and reduce project size.

3Smaller bundles improve parsing speed and reduce Largest Contentful Paint (LCP).

Performance Quiz - 3 Questions

How does using --inline-style and --inline-template flags when generating Angular components affect performance?

A Reduces bundle size by embedding styles and templates, improving load speed

B Increases bundle size by adding more files

C Has no effect on performance

D Causes more reflows during rendering

DevTools: Network

How to check: Open DevTools > Network tab, filter by JS and CSS files, and compare bundle sizes before and after using CLI flags.

What to look for: Look for reduced number and size of CSS and JS files indicating smaller bundles and faster load times.