refactor(helper): Rename Chain to Pipe and add Chain

Signed-off-by: Flc゛ <four_leaf_clover@foxmail.com>

helper/helper.go

@@ -32,6 +32,9 @@ func With[T any](value T, callbacks ...func(T) T) T {
 	return value
 }
 
+// Pipe is a function that takes a value and returns a value
+//
+//	Pipe(m1, m2, m3)(value) => m3(m2(m1(value)))
 func Pipe[T any](fns ...func(T) T) func(T) T {
 	return func(v T) T {
 		for _, fn := range fns {
@@ -41,6 +44,9 @@ func Pipe[T any](fns ...func(T) T) func(T) T {
 	}
 }
 
+// PipeWithErr is a function that takes a value and returns a value and an error
+//
+//	PipeWithErr(m1, m2, m3)(value) => m3(m2(m1(value)))
 func PipeWithErr[T any](fns ...func(T) (T, error)) func(T) (T, error) {
 	var err error
 	return func(v T) (T, error) {
@@ -53,6 +59,37 @@ func PipeWithErr[T any](fns ...func(T) (T, error)) func(T) (T, error) {
 	}
 }
 
+// Chain is a reverse Pipe
+//
+//	Chain(m1, m2, m3)(value) => m1(m2(m3(value)))
+func Chain[T any](fns ...func(T) T) func(T) T {
+	return func(v T) T {
+		for i := len(fns) - 1; i >= 0; i-- {
+			if fns[i] != nil {
+				v = fns[i](v)
+			}
+		}
+		return v
+	}
+}
+
+// ChainWithErr is a reverse PipeWithErr
+//
+//	ChainWithErr(m1, m2, m3)(value) => m1(m2(m3(value)))
+func ChainWithErr[T any](fns ...func(T) (T, error)) func(T) (T, error) {
+	var err error
+	return func(v T) (T, error) {
+		for i := len(fns) - 1; i >= 0; i-- {
+			if fns[i] != nil {
+				if v, err = fns[i](v); err != nil {
+					return v, err
+				}
+			}
+		}
+		return v, nil
+	}
+}
+
 func When[T any](value T, condition bool, callbacks ...func(T) T) T {
 	if condition {
 		return With(value, callbacks...)

helper/helper_test.go

@@ -340,3 +340,37 @@ func TestIf(t *testing.T) {
 	got = If(false, "foo", "bar")
 	assert.Equal(t, "bar", got)
 }
+
+func TestChain(t *testing.T) {
+	chain := Chain(func(s string) string {
+		return s + "1"
+	}, func(s string) string {
+		return s + "2"
+	})
+
+	got := chain("0")
+	assert.Equal(t, "021", got)
+}
+
+func TestChainWithErr(t *testing.T) {
+	chain := ChainWithErr(func(s string) (string, error) {
+		return s + "1", nil
+	}, func(s string) (string, error) {
+		return s + "2", nil
+	})
+
+	got, err := chain("0")
+	assert.Nil(t, err)
+	assert.Equal(t, "021", got)
+
+	// with error
+	chain2 := ChainWithErr(func(s string) (string, error) {
+		return s + "1", nil
+	}, func(s string) (string, error) {
+		return s + "2", assert.AnError
+	})
+
+	got, err = chain2("0")
+	assert.Error(t, err)
+	assert.Equal(t, "02", got)
+}