Simplify LINQ queries

marouaneterai · Dec 10, 2021 · a455eec · a455eec
1 parent c71f534
commit a455eec
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Showing 3 changed files with 17 additions and 21 deletions.
diff --git a/Tailspin.SpaceGame.Web/Controllers/HomeController.cs b/Tailspin.SpaceGame.Web/Controllers/HomeController.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using System.Linq.Expressions;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc;
 using TailSpin.SpaceGame.Web.Models;
@@ -47,7 +46,7 @@ public async Task<IActionResult> Index(
                     "Trio"
                 },
 
-                    GameRegions = new List<string>()
+                GameRegions = new List<string>()
                 {
                     "Milky Way",
                     "Andromeda",
@@ -60,10 +59,9 @@ public async Task<IActionResult> Index(
             try
             {
                 // Form the query predicate.
-                // This expression selects all scores that match the provided game 
-                // mode and region (map).
+                // Select all scores that match the provided game mode and region (map).
                 // Select the score if the game mode or region is empty.
-                Expression<Func<Score, bool>> queryPredicate = score =>
+                Func<Score, bool> queryPredicate = score =>
                     (string.IsNullOrEmpty(mode) || score.GameMode == mode) &&
                     (string.IsNullOrEmpty(region) || score.GameRegion == region);
 

diff --git a/Tailspin.SpaceGame.Web/IDocumentDBRepository.cs b/Tailspin.SpaceGame.Web/IDocumentDBRepository.cs
@@ -1,21 +1,21 @@
 using System;
 using System.Collections.Generic;
-using System.Linq.Expressions;
+using System.Linq;
 using System.Threading.Tasks;
-using TailSpin.SpaceGame.Web.Models;
-
+using TailSpin.SpaceGame.Web.Models;
+
 namespace TailSpin.SpaceGame.Web
 {
     public interface IDocumentDBRepository<T> where T : Model
-    {
+    {
         /// <summary>
         /// Retrieves the item from the store with the given identifier.
         /// </summary>
         /// <returns>
         /// A task that represents the asynchronous operation.
         /// The task result contains the retrieved item.
         /// </returns>
-        /// <param name="id">The identifier of the item to retrieve.</param>
+        /// <param name="id">The identifier of the item to retrieve.</param>
         Task<T> GetItemAsync(string id);
 
         /// <summary>
@@ -31,8 +31,8 @@ public interface IDocumentDBRepository<T> where T : Model
         /// <param name="page">The 1-based page of results to return.</param>
         /// <param name="pageSize">The number of items on a page.</param>
         Task<IEnumerable<T>> GetItemsAsync(
-            Expression<Func<T, bool>> queryPredicate,
-            Expression<Func<T, int>> orderDescendingPredicate,
+            Func<T, bool> queryPredicate,
+            Func<T, int> orderDescendingPredicate,
             int page = 1,
             int pageSize = 10
         );
@@ -45,6 +45,6 @@ Task<IEnumerable<T>> GetItemsAsync(
         /// The task result contains the number of items that match the query predicate.
         /// </returns>
         /// <param name="queryPredicate">Predicate that specifies which items to select.</param>
-        Task<int> CountItemsAsync(Expression<Func<T, bool>> queryPredicate);
+        Task<int> CountItemsAsync(Func<T, bool> queryPredicate);
     }
 }
diff --git a/Tailspin.SpaceGame.Web/LocalDocumentDBRepository.cs b/Tailspin.SpaceGame.Web/LocalDocumentDBRepository.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Linq.Expressions;
 using System.Threading.Tasks;
 using System.Text.Json;
 using TailSpin.SpaceGame.Web.Models;
@@ -46,17 +45,16 @@ public Task<T> GetItemAsync(string id)
         /// <param name="page">The 1-based page of results to return.</param>
         /// <param name="pageSize">The number of items on a page.</param>
         public Task<IEnumerable<T>> GetItemsAsync(
-            Expression<Func<T, bool>> queryPredicate,
-            Expression<Func<T, int>> orderDescendingPredicate,
+            Func<T, bool> queryPredicate,
+            Func<T, int> orderDescendingPredicate,
             int page = 1, int pageSize = 10
         )
         {
-            var result = _items.AsQueryable()
+            var result = _items
                 .Where(queryPredicate) // filter
                 .OrderByDescending(orderDescendingPredicate) // sort
                 .Skip(page * pageSize) // find page
-                .Take(pageSize) // take items
-                .AsEnumerable(); // make enumeratable
+                .Take(pageSize); // take items
 
             return Task<IEnumerable<T>>.FromResult(result);
         }
@@ -69,9 +67,9 @@ public Task<IEnumerable<T>> GetItemsAsync(
         /// The task result contains the number of items that match the query predicate.
         /// </returns>
         /// <param name="queryPredicate">Predicate that specifies which items to select.</param>
-        public Task<int> CountItemsAsync(Expression<Func<T, bool>> queryPredicate)
+        public Task<int> CountItemsAsync(Func<T, bool> queryPredicate)
         {
-            var count = _items.AsQueryable()
+            var count = _items
                 .Where(queryPredicate) // filter
                 .Count(); // count