Added concat

Author: p9ejAyeirtj

README.md

@@ -130,4 +130,13 @@ FindIndex(users, "User1")
 FindIndex(users, "User5")
 //-1
 
+```
+### Concat
+
+```
+users1 := []User{{Id: 10, Name: "John"}, {Id: 11, Name: "Doe"}, {Id: 12, Name: "Sabrina"}}
+users2 := []User{{Id: 10, Name: "John"}, {Id: 11, Name: "Doe"}, {Id: 12, Name: "Sabrina"}}
+Concat(users1, users2)
+//{{Id: 10, Name: "John"}, {Id: 11, Name: "Doe"}, {Id: 12, Name: "Sabrina"}, {Id: 10, Name: "John"}, {Id: 11, Name: "Doe"}, {Id: 12, Name: "Sabrina"}}
+
 ```

concat_test.go

@@ -0,0 +1,16 @@
+package js_array_method
+
+import (
+	"testing"
+)
+
+func TestConcat(t *testing.T) {
+	users1 := []User{{Id: 10, Name: "John"}, {Id: 11, Name: "Doe"}, {Id: 12, Name: "Sabrina"}}
+	users2 := []User{{Id: 10, Name: "John"}, {Id: 11, Name: "Doe"}, {Id: 12, Name: "Sabrina"}}
+
+	users := Concat(users1, users2)
+
+	if len(users) != 6 {
+		t.Errorf("Expected 6 got %d", len(users))
+	}
+}

js_array_method.go

@@ -120,3 +120,7 @@ func Reverse[T any](input []T) []T {
 
 	return output
 }
+
+func Concat[T any](slice1 []T, slice2 []T) []T {
+	return append(slice1, slice2...)
+}