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Angular Migration Guide

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Supported Migrations

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Before You Start

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1. Check Current State

npx depfixer

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2. Commit Current Changes

git add -A
git commit -m "chore: pre-migration checkpoint"

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Migration Steps

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Step 1: Run Migration Command

npx depfixer migrate

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Step 2: Select Target Version

Select target version:

    Angular 19 (Latest)
      -> 19.0.0 - Latest stable

  > Angular 18 (LTS)
      -> 18.2.0 - Long-term support

    Angular 17
      -> 17.3.0 - Stable

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Step 3: Review and Apply

✨ SUCCESS
──────────────────────────────────────────────────

    ✓ 12 Packages Updated
    ✓ Backup: package.json.bak

    👉 NEXT STEP:
    Run the following command to finalize changes:

    $ npm install

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Post-Migration Steps

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1. Install Dependencies

npm install

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2. Run Angular Schematics (Optional)

ng update @angular/core @angular/cli

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3. Fix Any Remaining Issues

npx depfixer
ng build

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TypeScript Versions

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Version-Specific Changes

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Angular 16 → 17

• Standalone by default - Components are standalone unless specified
• New control flow - @if, @for, @switch syntax
• Deferred loading - @defer for lazy loading

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Angular 17 → 18

• Zoneless support - Experimental zoneless change detection
• Signal-based inputs - input() function for reactive inputs
• New build system - application builder with esbuild

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Angular 18 → 19

• Incremental hydration - Partial hydration for SSR
• Resource API - Reactive data fetching primitives
• linkedSignal - Derived signals with reset capability

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Rollback

# Restore package.json
copy package.json.bak package.json  # Windows
cp package.json.bak package.json    # macOS/Linux

# Reinstall original dependencies
npm install