diff --git a/projects/ngrx.io/content/guide/data/entity-collection-service.md b/projects/ngrx.io/content/guide/data/entity-collection-service.md index c2596fd7f1..ba30ad0243 100644 --- a/projects/ngrx.io/content/guide/data/entity-collection-service.md +++ b/projects/ngrx.io/content/guide/data/entity-collection-service.md @@ -157,8 +157,10 @@ An entity argument **must never be a cached entity object**. It can be a _copy_ of a cached entity object and it often is. The demo application always calls these command methods with copies of the entity data. -All _command methods_ return `void`. +All _command methods_ return `void` or an `Observable`. A core principle of the _redux pattern_ is that _commands_ never return a value. They just _do things_ that have side-effects. +Thus, the action is only dispatched when the command is invoked, and re-subscribing to a command's returned `Observable` will not +dispatch another action. Rather than expect a result from the command, you subscribe to a _selector$_ property that reflects