Add IsEmpty/IsWhiteSpace and IsNullOrEmpty/WhiteSpace for string

CHANGELOG.md

@@ -56,6 +56,10 @@
 - X10D: Added `Span<T>.Split(Span<T>)`
 - X10D: Added `string.CountSubstring(char)`
 - X10D: Added `string.CountSubstring(string[, StringComparison])`
+- X10D: Added `string.IsEmpty()`
+- X10D: Added `string.IsWhiteSpace()`
+- X10D: Added `string.IsNullOrEmpty()`
+- X10D: Added `string.IsNullOrWhiteSpace()`
 - X10D: Added `TimeSpan.TryParse(ReadOnlySpan<char>, out TimeSpan)`
 - X10D: Added `Quaternion.Multiply(Vector3)` - this functions as an equivalent to Unity's `Quaternion * Vector3` operator
 - X10D: Added `Vector2.Deconstruct()`

X10D.Tests/src/Text/StringTests.cs

@@ -278,6 +278,32 @@ public class StringTests
         Assert.IsFalse("World".IsEmoji());
     }
 
+    [TestMethod]
+    public void IsEmpty_ShouldReturnTrue_GivenEmptyString()
+    {
+        Assert.IsTrue("".IsEmpty());
+        Assert.IsTrue(string.Empty.IsEmpty());
+    }
+
+    [TestMethod]
+    public void IsEmpty_ShouldReturnFalse_GivenWhiteSpaceString()
+    {
+        Assert.IsFalse(" ".IsEmpty());
+    }
+
+    [TestMethod]
+    public void IsEmpty_ShouldReturnFalse_GivenNonEmptyString()
+    {
+        Assert.IsFalse("Hello World".IsEmpty());
+    }
+
+    [TestMethod]
+    public void IsEmpty_ShouldThrowArgumentNullException_GivenNullString()
+    {
+        string? value = null;
+        Assert.ThrowsException<ArgumentNullException>(() => value!.IsEmpty());
+    }
+
     [TestMethod]
     public void IsLower_ShouldReturnTrue_GivenLowercaseString()
     {
@@ -303,6 +329,58 @@ public class StringTests
         Assert.ThrowsException<ArgumentNullException>(() => value!.IsLower());
     }
 
+    [TestMethod]
+    public void IsNullOrEmpty_ShouldReturnTrue_GivenEmptyString()
+    {
+        Assert.IsTrue("".IsNullOrEmpty());
+        Assert.IsTrue(string.Empty.IsNullOrEmpty());
+    }
+
+    [TestMethod]
+    public void IsNullOrEmpty_ShouldReturnFalse_GivenWhiteSpaceString()
+    {
+        Assert.IsFalse("   ".IsNullOrEmpty());
+    }
+
+    [TestMethod]
+    public void IsNullOrEmpty_ShouldReturnFalse_GivenNonEmptyString()
+    {
+        Assert.IsFalse("Hello World".IsNullOrEmpty());
+    }
+
+    [TestMethod]
+    public void IsNullOrEmpty_ShouldReturnTrue_GivenNullString()
+    {
+        string? value = null;
+        Assert.IsTrue(value.IsNullOrEmpty());
+    }
+
+    [TestMethod]
+    public void IsNullOrWhiteSpace_ShouldReturnTrue_GivenEmptyString()
+    {
+        Assert.IsTrue("".IsNullOrWhiteSpace());
+        Assert.IsTrue(string.Empty.IsNullOrWhiteSpace());
+    }
+
+    [TestMethod]
+    public void IsNullOrWhiteSpace_ShouldReturnTrue_GivenWhiteSpaceString()
+    {
+        Assert.IsTrue("   ".IsNullOrWhiteSpace());
+    }
+
+    [TestMethod]
+    public void IsNullOrWhiteSpace_ShouldReturnFalse_GivenNonEmptyString()
+    {
+        Assert.IsFalse("Hello World".IsNullOrWhiteSpace());
+    }
+
+    [TestMethod]
+    public void IsNullOrWhiteSpace_ShouldReturnTrue_GivenNullString()
+    {
+        string? value = null;
+        Assert.IsTrue(value.IsNullOrWhiteSpace());
+    }
+
     [TestMethod]
     public void IsPalindrome_ShouldBeCorrect_GivenString()
     {
@@ -358,6 +436,32 @@ public class StringTests
         Assert.ThrowsException<ArgumentNullException>(() => value!.IsUpper());
     }
 
+    [TestMethod]
+    public void IsWhiteSpace_ShouldReturnTrue_GivenEmptyString()
+    {
+        Assert.IsTrue("".IsWhiteSpace());
+        Assert.IsTrue(string.Empty.IsWhiteSpace());
+    }
+
+    [TestMethod]
+    public void IsWhiteSpace_ShouldReturnTrue_GivenWhiteSpaceString()
+    {
+        Assert.IsTrue("   ".IsWhiteSpace());
+    }
+
+    [TestMethod]
+    public void IsWhiteSpace_ShouldReturnFalse_GivenNonEmptyString()
+    {
+        Assert.IsFalse("Hello World".IsWhiteSpace());
+    }
+
+    [TestMethod]
+    public void IsWhiteSpace_ShouldThrowArgumentNullException_GivenNullString()
+    {
+        string? value = null;
+        Assert.ThrowsException<ArgumentNullException>(() => value!.IsWhiteSpace());
+    }
+
     [TestMethod]
     public void Randomize_ShouldReorder_GivenString()
     {

X10D/src/Text/StringExtensions.cs

@@ -1,4 +1,4 @@
-using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -409,6 +409,34 @@ public static class StringExtensions
         return EmojiRegex.Value.IsMatch(value);
     }
 
+    /// <summary>
+    ///     Returns a value indicating whether the current string represents an empty string.
+    /// </summary>
+    /// <param name="value">The value to check.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="value" /> is empty; otherwise, <see langword="false" />.
+    /// </returns>
+    /// <exception cref="ArgumentNullException"><paramref name="value" /> is <see langword="null" />.</exception>
+    [Pure]
+#if NETSTANDARD2_1
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+#else
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#endif
+    public static bool IsEmpty(this string value)
+    {
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(value);
+#else
+        if (value is null)
+        {
+            throw new ArgumentNullException(nameof(value));
+        }
+#endif
+
+        return value.Length == 0;
+    }
+
     /// <summary>
     ///     Determines if all alpha characters in this string are considered lowercase.
     /// </summary>
@@ -465,6 +493,46 @@ public static class StringExtensions
         return true;
     }
 
+    /// <summary>
+    ///     Returns a value indicating whether the current string is <see langword="null" /> (<see langword="Nothing" /> in Visual
+    ///     Basic), or represents an empty string.
+    /// </summary>
+    /// <param name="value">The value to check.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="value" /> is <see langword="null" /> or empty; otherwise,
+    ///     <see langword="false" />.
+    /// </returns>
+    [Pure]
+#if NETSTANDARD2_1
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+#else
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#endif
+    public static bool IsNullOrEmpty([NotNullWhen(false)] this string? value)
+    {
+        return string.IsNullOrEmpty(value);
+    }
+
+    /// <summary>
+    ///     Returns a value indicating whether the current string is <see langword="null" /> (<see langword="Nothing" /> in Visual
+    ///     Basic), represents an empty string, or consists of only whitespace characters.
+    /// </summary>
+    /// <param name="value">The value to check.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="value" /> is <see langword="null" />, empty, or consists of only
+    ///     whitespace; otherwise, <see langword="false" />.
+    /// </returns>
+    [Pure]
+#if NETSTANDARD2_1
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+#else
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#endif
+    public static bool IsNullOrWhiteSpace([NotNullWhen(false)] this string? value)
+    {
+        return string.IsNullOrWhiteSpace(value);
+    }
+
     /// <summary>
     ///     Determines whether the current string is considered palindromic; that is, the letters within the string are the
     ///     same when reversed.
@@ -602,6 +670,49 @@ public static class StringExtensions
         return true;
     }
 
+    /// <summary>
+    ///     Returns a value indicating whether the current string represents an empty string, or consists of only whitespace
+    ///     characters.
+    /// </summary>
+    /// <param name="value">The value to check.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="value" /> is empty or consists of only whitespace; otherwise,
+    ///     <see langword="false" />.
+    /// </returns>
+    /// <exception cref="ArgumentNullException"><paramref name="value" /> is <see langword="null" />.</exception>
+    [Pure]
+#if NETSTANDARD2_1
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+#else
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#endif
+    public static bool IsWhiteSpace(this string value)
+    {
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(value);
+#else
+        if (value is null)
+        {
+            throw new ArgumentNullException(nameof(value));
+        }
+#endif
+
+        if (value.Length == 0)
+        {
+            return true;
+        }
+
+        for (var index = 0; index < value.Length; index++)
+        {
+            if (!char.IsWhiteSpace(value[index]))
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     /// <summary>
     ///     Repeats a string a specified number of times.
     /// </summary>