Fix string indexOf for empty string

sebastienros · Jan 23, 2023 · 60dc6d0 · 60dc6d0
1 parent 57d1429
commit 60dc6d0
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/Jint.Tests/Runtime/StringTests.cs b/Jint.Tests/Runtime/StringTests.cs
@@ -55,4 +55,12 @@ public void HasProperIteratorPrototypeChain()
         Assert.True(engine.Evaluate("!iterator.hasOwnProperty(Symbol.iterator)").AsBoolean());
         Assert.True(engine.Evaluate("iterator[Symbol.iterator]() === iterator").AsBoolean());
     }
+
+    [Fact]
+    public void IndexOf()
+    {
+        var engine = new Engine();
+        Assert.Equal(0, engine.Evaluate("''.indexOf('', 0)"));
+        Assert.Equal(0, engine.Evaluate("''.indexOf('', 1)"));
+    }
 }
diff --git a/Jint/Native/String/StringPrototype.cs b/Jint/Native/String/StringPrototype.cs
@@ -799,9 +799,9 @@ private JsValue IndexOf(JsValue thisObj, JsValue[] arguments)
                 pos = TypeConverter.ToInteger(arguments[1]);
             }
 
-            if (pos >= s.Length)
+            if (pos > s.Length)
             {
-                return JsNumber.IntegerNegativeOne;
+                pos = s.Length;
             }
 
             if (pos < 0)