Dependency Update — Frontend (Angular)

Audit and update npm packages safely, with breaking change detection.

Stack: Angular/TypeScript (npm)

When to Use

• Routine npm dependency maintenance
• Security vulnerability response (npm audit)
• Angular framework upgrades (Angular 19→20, TypeScript bumps)
• Before starting a new feature (ensure clean baseline)

Core Principle

Never apply major version bumps without user confirmation. Major versions mean breaking changes — API removals, behavioral changes, migration schematics. Always show what changed and ask before proceeding.

Workflow

1. AUDIT       → npm outdated / npm audit / ng update
2. TRIAGE      → Classify as patch / minor / major / security
3. UPDATE      → Patch → verify → Minor → verify → Major → ASK → verify
4. VERIFY      → ng build && ng test after each batch

Phase 1: Audit

# Outdated packages (color-coded: red=in-range, yellow=major bump)
npm outdated

# Security audit
npm audit

# Angular-specific update check
ng update

Optional tools

# npm-check-updates (color-coded risk: red=major, cyan=minor, green=patch)
npx npm-check-updates

# Doctor mode — auto-tests each upgrade to find which ones break
npx npm-check-updates --doctor

Phase 2: Triage

Present a report to the user:

DEPENDENCY UPDATE REPORT — Frontend (Angular)
===============================================

Patch (safe):
  rxjs                     7.8.0 → 7.8.1
  zone.js                  0.14.3 → 0.14.4

Minor (review):
  @angular/material       17.2.0 → 17.3.0
  @ngrx/store              17.1.0 → 17.2.0

Major (BREAKING — needs confirmation):
  ⚠ @angular/core          17.3.0 → 18.0.0
  ⚠ typescript              5.3.3 → 5.5.0
  ⚠ rxjs                    7.8.1 → 8.0.0

Security:
  🔒 express               4.18.2 → 4.19.2  (CVE-2024-XXXX)

Risk levels

Note: npm update respects semver ranges and will never auto-install major versions. Major bumps always require explicit action.

Phase 3: Update

Step 1: Security fixes (urgent)

# Auto-fix what it can (safe updates only)
npm audit fix

# NEVER blindly run this — may install breaking major versions:
# npm audit fix --force

→ Run verification (ng build && ng test --watch=false)

Step 2: Patch updates (safe)

# Respects semver ranges, only applies patches
npm update

→ Run verification

Step 3: Minor updates (review)

Apply one by one:

npm install <package>@<latest-minor>

→ Run verification

Step 4: Major updates (STOP AND ASK)

Never auto-apply. For each major bump:

1. Show the user what's changing:

   Copy

   ⚠ MAJOR VERSION UPDATE: @angular/core 17.3.0 → 18.0.0
   
   Breaking changes:
   - New control flow syntax (@if/@for replace *ngIf/*ngFor)
   - Signals become primary reactivity model
   - Karma test runner deprecated (migrate to Jest/Vitest)
   
   Impact: 47 files import from @angular/core
   Migration guide: https://angular.dev/update-guide
   
   Files likely needing changes:
   - All component templates (control flow migration)
   - app.config.ts (new providers pattern)
   - karma.conf.js (test runner migration)
   
   Proceed? (yes/no/skip)
   

2. If user confirms: use ng update, run schematics, check build, run tests

Impact Analysis

# How many files import this?
grep -rn "from '<package>'" --include="*.ts" src/ | wc -l

# Which files?
grep -rln "from '<package>'" --include="*.ts" src/

Breaking Change Detection

How to identify

1. SemVer major bump → always assume breaking
2. Angular update guide — check angular.dev/update-guide
3. ng update schematics — auto-migrate known patterns
4. TypeScript wiki — check github.com/microsoft/TypeScript/wiki/Breaking-Changes
5. Build after update — compiler errors reveal API changes

Common breaking changes by package

Angular Framework Upgrade

Angular upgrades have a specific workflow:

1. Check angular.dev/update-guide for migration guide
2. ng update @angular/core @angular/cli
3. Run migration schematics (automatic code transforms)
4. ng build → fix compiler errors
5. ng test --watch=false → fix test failures
6. Update third-party Angular packages to compatible versions
7. Check for deprecated APIs (Angular compiler warnings)

Always update @angular/core FIRST, then third-party packages.

Version-by-version approach

For multi-version jumps (e.g., Angular 16→19), upgrade one major version at a time:

ng update @angular/core@17 @angular/cli@17
# test, fix, commit
ng update @angular/core@18 @angular/cli@18
# test, fix, commit
ng update @angular/core@19 @angular/cli@19
# test, fix, commit

Verification

After each batch:

ng build 2>&1 | tail -20
ng test --watch=false 2>&1 | tail -30

Rollback

# Restore from lock file
rm -rf node_modules
npm ci

# Revert specific package
npm install <package>@<previous-version>

# Nuclear option
git checkout -- package.json package-lock.json
npm ci

Flags

Anti-Patterns

• Updating everything at once — one major bump breaks, but which one?
• npm audit fix --force — may install breaking major versions silently
• Updating Angular packages before @angular/core — version mismatches cause cryptic errors
• Skipping migration schematics — ng update schematics fix known patterns automatically
• Pinning exact versions forever — security vulnerabilities accumulate
• Ignoring TypeScript version requirements — Angular requires specific TypeScript ranges