Add types.MakeBool with variadic transformer functions

This is analogous to the `MakeInt` and `MakeString` functions but for Bool.

Author: yhabteab

types/bool.go

@@ -22,6 +22,28 @@ type Bool struct {
 	Valid bool // Valid is true if Bool is not NULL
 }
 
+// TransformZeroBoolToNull is a transformer function that sets the Valid field to false if the Bool is zero.
+// This is useful when you want to convert a zero value to a NULL value in a database context.
+func TransformZeroBoolToNull(b *Bool) {
+	if b.Valid && !b.Bool {
+		b.Valid = false
+	}
+}
+
+// MakeBool constructs a new Bool.
+//
+// Multiple transformer functions can be given, each transforming the generated Bool to whatever is needed.
+// If no transformers are given, the Bool will be valid and set to the given value.
+func MakeBool(bi bool, transformers ...func(*Bool)) Bool {
+	b := Bool{Bool: bi, Valid: true}
+
+	for _, transformer := range transformers {
+		transformer(&b)
+	}
+
+	return b
+}
+
 // IsZero implements the json.isZeroer interface.
 // A Bool is considered zero if its Valid field is false regardless of its actual Bool value.
 func (b Bool) IsZero() bool { return !b.Valid }

types/bool_test.go

@@ -7,6 +7,46 @@ import (
 	"unicode/utf8"
 )
 
+func TestMakeBool(t *testing.T) {
+	t.Parallel()
+
+	subtests := []struct {
+		name         string
+		input        bool
+		transformers []func(*Bool)
+		output       Bool
+	}{
+		{
+			name:   "false",
+			input:  false,
+			output: Bool{Bool: false, Valid: true},
+		},
+		{
+			name:   "true",
+			input:  true,
+			output: Bool{Bool: true, Valid: true},
+		},
+		{
+			name:         "false-transform-zero-to-null",
+			input:        false,
+			transformers: []func(*Bool){TransformZeroBoolToNull},
+			output:       Bool{Valid: false},
+		},
+		{
+			name:         "true-transform-zero-to-null",
+			input:        true,
+			transformers: []func(*Bool){TransformZeroBoolToNull},
+			output:       Bool{Bool: true, Valid: true},
+		},
+	}
+
+	for _, st := range subtests {
+		t.Run(st.name, func(t *testing.T) {
+			require.Equal(t, st.output, MakeBool(st.input, st.transformers...))
+		})
+	}
+}
+
 func TestBool_MarshalJSON(t *testing.T) {
 	subtests := []struct {
 		input  Bool