In NPM package naming, the "@" prefix is used to indicate that a package belongs to a specific scope. A scope is a namespace controlled by a user or organization, which helps in managing and organizing related packages while avoiding naming conflicts. Using scopes ensures the uniqueness of package names because even if the same package name exists under different scopes, they are still considered completely distinct packages.
For example, the Angular team has many related packages placed under the @angular scope, such as @angular/core, @angular/common, etc. This not only clearly indicates that these packages are related to Angular but also avoids naming conflicts with non-Angular packages like core or common.
The process of creating and publishing scoped packages is similar to that of regular packages, but the scope prefix must be included in the naming. For example, if I create a package named example and want to place it under my personal scope @myusername, the full package name should be @myusername/example.
When installing scoped packages, the scope prefix must also be included, for example, using the command npm install @angular/core.