feat: FetchExt::filtered

src/fetch/ext.rs

@@ -1,6 +1,6 @@
 use crate::{
     component::ComponentValue,
-    filter::{Cmp, Equal, Greater, GreaterEq, Less, LessEq},
+    filter::{Cmp, Equal, Filtered, Greater, GreaterEq, Less, LessEq},
     relation::RelationExt,
     Fetch, FetchItem,
 };
@@ -198,6 +198,15 @@ pub trait FetchExt: Sized {
     {
         Map { query: self, func }
     }
+
+    /// Filter a fetch with another fetch as predicate
+    fn filtered<F>(self, filter: F) -> Filtered<Self, F>
+    where
+        Self: for<'x> FetchItem<'x>,
+        F: for<'x> Fetch<'x>,
+    {
+        Filtered::new(self, filter, true)
+    }
 }
 
 impl<F> FetchExt for F where F: for<'x> Fetch<'x> {}