added single and singleordefault

dev/Helper.ts

@@ -169,8 +169,10 @@
             new EvaluateCommand("OrderBy", "orderby {x} ascending", "order by {x} ascending", "orderbyascending {x}", "order by ascending {x}", "orderby {x}", "order by {x}"),
             new EvaluateCommand("FirstOrDefault", "firstordefault {x}", "first or default {x}", "firstordefault", "first or default"),
             new EvaluateCommand("LastOrDefault", "lastordefault {x}", "last or default {x}", "lastordefault", "last or default"),
+            new EvaluateCommand("SingleOrDefault", "singleordefault {x}", "single or default {x}", "singleordefault", "single or default"),
             new EvaluateCommand("First", "first {x}", "first"),
             new EvaluateCommand("Last", "last {x}", "last"),
+            new EvaluateCommand("Single", "single {x}", "single"),
             new EvaluateCommand("ThenByDescending", "thenby {x} descending", "then by {x} descending", "thenbydescending {x}", "then by descending {x}"),
             new EvaluateCommand("ThenBy", "thenby {x} ascending", "then by {x} ascending", "thenbyascending {x}", "then by ascending {x}", "thenby {x}", "then by {x}")
         ];

dev/IArray.ts

@@ -135,6 +135,18 @@
      */
     FirstOrDefault(filter?: ((item: T) => boolean) | string): (T | null);
 
+    /**
+     * Returns the only item of the array - Throws an exception if not exactly one item is in array
+     * @param filter If set the function returns the only item that matches the filter
+     */
+    Single(filter?: ((item: T) => boolean) | string): T;
+
+    /**
+     * Returns the only item of the array - Throws an exception if not only one item is in array
+     * @param filter If set the function returns the only item that matches the filter
+     */
+    SingleOrDefault(filter?: ((item: T) => boolean) | string): (T | null);
+
     /**
      * Returns the last item of the array - Throws an exception if no item was found
      * @param filter If set the function returns the last item that matches the filter

dev/Modules/Single.ts

@@ -0,0 +1,19 @@
+Array.prototype.Single = function<T> (this: T[], filter?: ((item: T) => boolean) | string): (T | null) {
+    let that: T[] = this;
+
+    if (filter != null) {
+        let result: T[] = that.Where(filter);
+
+        if (result.Count() === 1) {
+            return result.Get(0);
+        } else {
+            throw new Error("Linq4JS: The array does not contain exactly one element");
+        }
+    } else {
+        if (that.Count() === 1) {
+            return that.Get(0);
+        } else {
+            throw new Error("Linq4JS: The array does not contain exactly one element");
+        }
+    }
+};

dev/Modules/SingleOrDefault.ts

@@ -0,0 +1,27 @@
+Array.prototype.SingleOrDefault = function<T> (this: T[], filter?: ((item: T) => boolean) | string): (T | null) {
+    let that: T[] = this;
+
+    if (filter != null) {
+        let result: T[] = that.Where(filter);
+
+        if (result.Count() === 1) {
+            return result.Get(0);
+        } else {
+            if (result.Count() > 1) {
+                throw new Error("Linq4JS: The array contains more than one element");
+            } else {
+                return null;
+            }
+        }
+    } else {
+        if (that.Count() === 1) {
+            return that.Get(0);
+        } else {
+            if (that.Count() > 1) {
+                throw new Error("Linq4JS: The array contains more than one element");
+            } else {
+                return null;
+            }
+        }
+    }
+};

dist/linq4js.d.ts

@@ -142,6 +142,16 @@ interface Array<T> {
      * @param filter If set the function returns the first item that matches the filter
      */
     FirstOrDefault(filter?: ((item: T) => boolean) | string): (T | null);
+    /**
+     * Returns the only item of the array - Throws an exception if not exactly one item is in array
+     * @param filter If set the function returns the only item that matches the filter
+     */
+    Single(filter?: ((item: T) => boolean) | string): T;
+    /**
+     * Returns the only item of the array - Throws an exception if not only one item is in array
+     * @param filter If set the function returns the only item that matches the filter
+     */
+    SingleOrDefault(filter?: ((item: T) => boolean) | string): (T | null);
     /**
      * Returns the last item of the array - Throws an exception if no item was found
      * @param filter If set the function returns the last item that matches the filter

package.json

@@ -1,6 +1,6 @@
 {
   "name": "linq4js",
-  "version": "2.1.6",
+  "version": "2.1.7",
   "description": "Linq methods for JavaScript/TypeScript for working with Arrays",
   "main": "dist/linq4js.js",
   "typings": "dist/linq4js.d.ts",