Merge branch 'master' of https://github.com/Microsoft/UWPCommunityToolkit into MakeMarkdownUniversalAgain

Microsoft.Toolkit/Extensions/StringExtensions.cs

@@ -0,0 +1,34 @@
+// ******************************************************************
+// Copyright (c) Microsoft. All rights reserved.
+// This code is licensed under the MIT License (MIT).
+// THE CODE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH
+// THE CODE OR THE USE OR OTHER DEALINGS IN THE CODE.
+// ******************************************************************
+
+using System.Text.RegularExpressions;
+
+namespace Microsoft.Toolkit.Extensions
+{
+    /// <summary>
+    /// All common string extensions should go here
+    /// </summary>
+    public static class StringExtensions
+    {
+        internal const string EmailRegex = "(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])";
+
+        /// <summary>
+        /// Returns whether said string is a valid email or not.
+        /// Uses general Email Regex (RFC 5322 Official Standard) from emailregex.com
+        /// </summary>
+        /// <returns><c>true</c> for valid email.<c>false</c> otherwise</returns>
+        public static bool IsEmail(this string str)
+        {
+            return Regex.IsMatch(str, EmailRegex);
+        }
+    }
+}