Angular新手求助：编译报错Cannot read property 'isSkipSelf' of null但应用正常

Hey there! No worries at all—we’ve all stumbled through weird Angular errors when starting out, so don’t sweat how you phrased the question. 😊

That Cannot read property 'isSkipSelf' of null error is a tricky one because it pops up during compilation but doesn’t break your app’s functionality. Let’s walk through some common fixes:

• Fix dependency version mismatches
  This error often crops up when there’s a version conflict between Angular CLI, @angular/core, or related packages. Since your package.json is truncated, first make sure all your Angular-related dependencies are on compatible versions. Try these steps:

  1. Delete your node_modules folder and package-lock.json (or yarn.lock if you use Yarn)
  2. Run npm install to reinstall dependencies fresh
  3. If you’re on an older Angular version, update your CLI and core packages to matching versions:

     npm install -g @angular/cli@latest
     ng update @angular/cli @angular/core
     

• Check your dependency injection code
  isSkipSelf is tied to Angular’s dependency injection system. The error might be flagging a potential issue with how you’re injecting services—even if it’s not breaking runtime behavior yet. Look for any recent changes where you used decorators like @SkipSelf() or @Optional() in component/service constructors. For example, double-check code like this:

  constructor(@SkipSelf() private myService: MyService) {}
  

  Make sure the service is properly provided in the right injector hierarchy (e.g., not missing a provider in a parent component or module).

• Clear Angular’s build cache
  Stale cache files can cause all sorts of odd compilation errors. Try clearing the cache with:

  ng cache clean
  

  If that doesn’t work, manually delete the .angular/cache folder in your project root, then run ng build again.

If none of these work, sharing the full package.json (especially the dependencies and devDependencies sections) would help narrow things down further.

内容的提问来源于stack exchange，提问作者user3782645