What does “@” symbol mean in “import { Component }

问题:

I'm reading Angular 2 "5 Min Quickstart" and there is such a line:

import { Component } from '@angular/core';"

I can't figure out, what does @ symbol make in that import? TypeScript docs also don't say anything about that.

What does it mean?

回答1:

Also of relevance is that you can use the @ symbol scoping for non-npm packages as well. You can use this in your project as a short way of referring to different directories.

i.e.

import { MyService } from '@services/my.service';
import { HelloWorldComponent } from '@components/hello-world.component';

instead of

import { MyService } from '../../../../my.service';
import { HelloWorldComponent } from '../shared/deeply/nested/hello-world/hello-world.component';

To do this, you simply configure your tsconfig.json file (at root of project) like this:

{
  "compileOnSave": false,
  "compilerOptions": {

    // omitted...

    "baseUrl": "src",
    "paths": {
      "@services/*": ["app/path/to/services/*"],
      "@components/*": ["app/somewhere/deeply/nested/*"],
      "@environments/*": ["environments/*"]
    }
  }
}

See the full details at Angular Firebase

回答2:

@scope_name/package_name

This is NPM feature, scoped name, anything between @ and slash / will be your scope name.

npm scope document

回答3:

this is just a naming convention that Angular uses. Since the release they renamed it to @angular/core in stead of angular2/core.

It references the core components of the framework.

(found in post - angularjs 2 with angular-material @angular/core not found)