Angular 7 to Angular 8.2 Upgrade

Purpose

Use this skill to upgrade an Angular 7.x application to Angular 8.2.x in one bounded major hop.

This skill upgrades only from Angular 7 to Angular 8.2. It must not continue to Angular 9 or later. The next hop must be handled by a dedicated follow-up skill.

When to Use

Use this skill when:

• The project is currently on Angular 7.x.
• The target hop is Angular 8.2.x.
• The route planner selected 7 -> 8 as the next step.
• The previous Angular 6+ validation gate passed or the remaining risks were accepted.
• The workspace uses angular.json.
• Angular CLI, RxJS, and workspace status are known.
• Angular Material usage is known.
• Style strategy is known.

When Not to Use This Skill

Do not use this skill when:

• The project is AngularJS 1.x.
• The project is Angular 6.x or lower.
• The project is already Angular 8 or later.
• The previous Angular 6 -> 7 validation gate failed.
• Workspace status is unknown.
• RxJS status is unknown.
• Angular Material version is unknown in a Material project.
• The requested change is Angular 8 to Angular 9.
• The task is only a style cleanup without Angular upgrade.
• The task is only Angular Material migration without Angular core upgrade.

For Angular 8 to Angular 9, route to:

skills/angular/upgrades/hops/angular-8-to-9/SKILL.md

Inputs Expected

• package.json
• lock file: package-lock.json, yarn.lock, or pnpm-lock.yaml
• Angular package versions
• Angular CLI version
• Angular Material version
• Angular CDK version
• TypeScript version
• RxJS version
• rxjs-compat usage
• Zone.js version
• Node.js version
• angular.json
• browserslist
• .browserslistrc
• tsconfig.json
• tsconfig.app.json
• tsconfig.spec.json
• polyfills.ts
• use of Angular Service Worker
• use of screenshot/golden tests
• use of SCSS/Sass
• use of node-sass
• use of /deep/
• use of ::ng-deep
• use of @angular/material barrel imports
• use of lazy route string syntax
• use of ViewChild
• use of ContentChild
• use of @angular/platform-webworker
• use of wtf* tracing APIs
• use of custom schematics
• use of legacy HttpModule
• use of Http
• use of deprecated Material ripple APIs
• current build/test/lint/e2e scripts

Compatibility by Version

Area	Recommended strategy	Observations
Angular 7.x source	Upgrade to Angular 8.2.x only	Do not jump to a later major in this skill.
Angular CLI	Upgrade to CLI 8	Keep workspace validation explicit.
TypeScript	Align to Angular 8-compatible TypeScript 3.4	Verify against project evidence.
RxJS	Keep RxJS 6 cleanup explicit and remove rxjs-compat when safe	Treat rxjs-compat as temporary if retained.
Angular Material	Upgrade to Material 8 only if used	Do not go beyond Angular 8 in this hop.

If a version cannot be confirmed from the project files, mark it as verify in project.

Procedure

1. Inspect dependency versions and lockfile evidence.
2. Check Node.js, CLI, workspace, and validation-gate status.
3. Scan the codebase for Angular 7-era deprecated or risky APIs.
4. Classify each occurrence by impact and required change.
5. Apply the bounded dependency upgrade to Angular 8.2.
6. Convert only the code required by the hop.
7. Run validation commands that exist in the repository.
8. Set the gate result explicitly.
9. Stop after Angular 8.2. Do not begin the next hop.

Do

• Keep the hop bounded to Angular 7 -> Angular 8.2.
• Check CLI workspace, Material, styles, lazy routes, queries, differential loading, browserslist, rxjs-compat, HttpModule/Http, and service worker status.
• Remove rxjs-compat only when no legacy imports or third-party requirements remain and validation passes without it.
• Use the previous validation gate as a hard gate condition.
• Stop after validation and report the next hop.

Recommended Patterns

Upgrade Angular packages to Angular 8.2-compatible versions using the project-supported package manager and CLI workflow.

Use ng update or the repository-supported equivalent for Angular CLI 8 and Angular core 8.

Replace /deep/ with ::ng-deep as a temporary compatibility step:

:host ::ng-deep .child {
  color: red;
}

Make ViewChild and ContentChild query timing explicit:

@ViewChild('foo', { static: false }) foo!: ElementRef;

Convert string lazy routes to dynamic imports:

{
  path: 'admin',
  loadChildren: () => import('./admin/admin.module').then(m => m.AdminModule)
}

Treat the validation gate as part of the hop, not a later concern.

Anti-Patterns

• Jumping from Angular 7 directly to Angular 21.
• Starting Angular 9 migration in the same change.
• Updating Angular Material beyond v8.
• Ignoring style changes caused by Material or Sass compiler changes.
• Replacing /deep/ with global CSS as a shortcut.
• Accepting all ViewChild static values blindly in critical components.
• Leaving string lazy routes for Angular 9 without documenting the blocker.
• Adding node-sass preemptively.
• Opting into CLI analytics silently.
• Regenerating screenshot golden files blindly.
• Removing AngularJS from hybrid apps during this hop.
• Introducing standalone components or signals.
• Claiming success without build/test validation.
• Passing the gate when CLI, core, Material, styles, or build target status is unknown.

Do Not

• Do not continue to Angular 9 or later.
• Do not change unrelated application architecture.
• Do not force later Angular patterns into this hop.
• Do not run commands that do not exist in package.json.
• Do not claim completion without validation evidence.

Review Checklist

• Angular 7.x source version was confirmed.
• Angular packages were aligned to Angular 8.2.x.
• CLI workspace status was checked.
• TypeScript compatibility was checked.
• RxJS compatibility was checked.
• rxjs-compat status was checked.
• Deprecated APIs were classified and handled.
• Styles and query timing were reviewed.
• Lazy routes were reviewed.
• Material and Service Worker changes were reviewed where applicable.
• Validation commands were run or explicitly unavailable.
• Validation gate result was explicit.
• The next hop was not started automatically.

Validation Minimum

Read package.json first. Only run scripts that exist.

Preferred order when available:

• build
• test
• lint
• e2e

For Angular CLI projects, use direct CLI commands only if they exist in the project.

For screenshot/golden tests, run them only if scripts exist.

If validation fails, report:

• command
• error summary
• likely cause
• safe next action
• whether the next hop is blocked

Validation Gate

This hop must close with an explicit gate decision.

Gate result must be one of:

PASS
PASS_WITH_WARNINGS
FAIL_BLOCK_NEXT_HOP

Use FAIL_BLOCK_NEXT_HOP when:

• build fails
• tests fail
• Angular CLI update is incomplete
• Angular Material update is incomplete in a Material project
• style migration has unresolved breakage
• /deep/ usage remains without documentation
• ViewChild / ContentChild query migration is incomplete
• lazy route string syntax remains without documentation
• rxjs-compat status is unknown
• legacy HttpModule status is unknown
• es5BrowserSupport / differential loading status is unknown
• screenshot changes are unreviewed
• workspace config is unstable

Risks

• CLI and Material upgrades can cascade into build and visual regressions.
• /deep/ replacement may surface style encapsulation issues.
• Query timing changes can break critical component lifecycle assumptions.
• Lazy route conversion can break route loading if paths are incorrect.

Expected Output

When this skill is used, return:

1. Source Angular version.
2. Target Angular version.
3. Angular CLI and workspace status.
4. Applied dependency and code changes.
5. Validation commands and results.
6. Gate result.
7. Remaining risks.
8. Next hop skill.

Exit Criteria

This skill is complete only when:

• Angular packages are upgraded to Angular 8.2-compatible versions.
• Angular CLI is upgraded to v8.
• Angular Material/CDK are upgraded to v8 only if used.
• TypeScript is aligned to Angular 8-compatible TypeScript 3.4.
• Node.js 10+ compatibility has been confirmed.
• /deep/ is replaced with ::ng-deep or documented.
• ViewChild and ContentChild queries include explicit static values.
• String lazy routes are migrated to dynamic imports or documented as blockers.
• Material imports use specific entry points instead of @angular/material.
• rxjs-compat is removed or explicitly documented.
• Legacy HttpModule / Http usage is removed or explicitly documented.
• Validation ran or blockers were reported.
• Validation gate result is explicit.
• The next hop remains unexecuted.