refactor: change common package to condition package

* feat:(slice add AppendIfAbsent function)

* feat:(slice add TernaryOperator function)

Co-authored-by: george.zheng <george.zheng@ambergroup.io>

condition/condition.go

@@ -0,0 +1,14 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package condition contains some functions for conditional judgment. eg. And, Or, TernaryOperator ...
+package condition
+
+// TernaryOperator if true return trueValue else return falseValue
+func TernaryOperator[T any](isTrue bool, trueValue T, falseValue T) T {
+	if isTrue {
+		return trueValue
+	} else {
+		return falseValue
+	}
+}

condition/condition_test.go

@@ -0,0 +1,15 @@
+package condition
+
+import (
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func TestTernaryOperator(t *testing.T) {
+	assert := internal.NewAssert(t, "TernaryOperator")
+	trueValue := "1"
+	falseValue := "0"
+
+	assert.Equal(trueValue, TernaryOperator(true, trueValue, falseValue))
+}