Angular 5.6升级至6.0（RxJS 6.0）迁移方案及依赖问题咨询

Upgrade Scripts & Low-Code Migration Options #

• Angular 6 introduced the official ng update command, which is the go-to automated migration tool. Here's a step-by-step approach:
  1. First, confirm your environment meets the requirements: Node.js 8.x or higher, npm 5.6+
  2. Run ng update @angular/cli – this updates the CLI and converts your old .angular-cli.json to the new angular.json configuration file
  3. Run ng update @angular/core – this handles core package upgrades and automatically fixes many breaking changes (like adjusting deprecated APIs where possible)
• Is a zero-code upgrade possible? For very simple apps with minimal custom code and dependencies, you might get away with just running the above commands without manual tweaks. However, Angular 6 does have some breaking changes (e.g., router behavior adjustments, HttpClient interceptor updates, deprecated pipe syntax) that could require small fixes depending on your app's complexity. Always run thorough tests after upgrading.

Fixing the HttpClientModule Import Issue #

Your import statement (import { HttpClientModule } from '@angular/common/http';) is fully correct for Angular 6 – that's the proper location for this module. The "missing reference" error typically stems from one of these issues:

• Incomplete dependency installation: Delete your node_modules folder and package-lock.json (or yarn.lock if using Yarn), then run npm install to re-install all dependencies from scratch
• Misconfigured TypeScript settings: Check your tsconfig.json to ensure baseUrl is set correctly (usually to ".") and there are no conflicting paths entries blocking access to @angular/common
• Stale CLI cache: Run ng clean to clear the Angular CLI cache, then restart your development server

内容的提问来源于stack exchange，提问作者Joe