Better functional option for setting redact hint (#33)

Better functional option for setting redact hint

Instead of having multiple optional functions for setting redact hint,
now we have just one takes any string as redact hint. We still provide
common redact hints but now as simple constants. This approach is a lot
cleaner than before. Adjust tests accordingly.

Extras: Renamed receiver var to `tx` in all methods and functions for
consistency.

Author: rsjethani

example_test.go

@@ -10,31 +10,31 @@ import (
 func ExampleText() {
 	s := secret.Text{}
 	fmt.Println(s, s.Value())
+
 	// Output: *****
 }
 
 func ExampleNew() {
 	s := secret.New("$ecre!")
 	fmt.Println(s, s.Value())
+
 	// Output: ***** $ecre!
 }
 
-func ExampleFiveXs() {
-	s := secret.New("$ecre!", secret.FiveXs)
+func ExampleRedactHint() {
+	s := secret.New("$ecre!", secret.RedactHint(secret.FiveX))
 	fmt.Println(s, s.Value())
-	// Output: XXXXX $ecre!
-}
 
-func ExampleRedacted() {
-	s := secret.New("$ecre!", secret.Redacted)
+	s = secret.New("$ecre!", secret.RedactHint(secret.Redacted))
 	fmt.Println(s, s.Value())
-	// Output: [REDACTED] $ecre!
-}
 
-func ExampleCustomRedact() {
-	s := secret.New("$ecre!", secret.CustomRedact("HIDDEN"))
+	s = secret.New("$ecre!", secret.RedactHint("my redact hint"))
 	fmt.Println(s, s.Value())
-	// Output: HIDDEN $ecre!
+
+	// Output:
+	// XXXXX $ecre!
+	// [REDACTED] $ecre!
+	// my redact hint $ecre!
 }
 
 func ExampleText_MarshalText() {
@@ -52,6 +52,7 @@ func ExampleText_MarshalText() {
 	}
 
 	fmt.Println(string(bytes))
+
 	// Output: {"User":"John","Password":"*****"}
 }
 
@@ -68,6 +69,7 @@ func ExampleText_UnmarshalText() {
 
 	fmt.Printf("%+v\n", login)
 	fmt.Println(login.Password.Value())
+
 	// Output:
 	// {User:John Password:*****}
 	// $ecre!
@@ -79,6 +81,7 @@ func ExampleText_Equals() {
 	s3 := secret.New("hi")
 	fmt.Println(s1.Equals(s2))
 	fmt.Println(s1.Equals(s3))
+
 	// Output:
 	// true
 	// false

secret.go

@@ -5,92 +5,85 @@
 package secret
 
 // Text provides a way to safely store your secret value and a corresponding redact hint. This
-// redact hint what is used in operations like printing and serializing. The default
-// value of Text is usable.
+// redact hint is what is used in operations like printing and serializing.
 type Text struct {
 	// v is the actual secret values.
 	v *string
 	// r is the redact hint to be used in place of secret.
 	r *string
 }
 
-// New returns [Text] for the secret with `*****` as the redact hint.
-// Multiple option functions can be passed to alter default behavior.
+// New returns [Text] for the secret with [FiveStar] as the default redact hint. Provide options
+// like [RedactHint] to modify default behavior.
 func New(secret string, options ...func(*Text)) Text {
-	sec := Text{
+	tx := Text{
 		v: new(string),
 		r: new(string),
 	}
 
-	*sec.v = secret
-	*sec.r = defaultRedact
+	*tx.v = secret
+	*tx.r = FiveStar
 
-	// Apply options to override defaults
-	for _, opt := range options {
-		opt(&sec)
+	for _, o := range options {
+		o(&tx)
 	}
 
-	return sec
+	return tx
 }
 
-// defaultRedact is used if no other redact hint is given.
-const defaultRedact string = "*****"
+// Some common redact hints.
+const (
+	FiveX    string = "XXXXX"
+	FiveStar string = "*****"
+	Redacted string = "[REDACTED]"
+)
 
-// String implements the fmt.Stringer interface and returns only the redact hint. This prevents the
+// RedactHint is a functional option to set r as the redact hint for the [Text]. You can use one of
+// the common redact hints provided with this package like [FiveX] or provide your own string.
+func RedactHint(r string) func(*Text) {
+	return func(t *Text) {
+		*t.r = r
+	}
+}
+
+// String implements the [fmt.Stringer] interface and returns only the redact hint. This prevents the
 // secret value from being printed to std*, logs etc.
-func (s Text) String() string {
-	if s.r == nil {
-		return defaultRedact
+func (tx Text) String() string {
+	if tx.r == nil {
+		return FiveStar
 	}
-	return *s.r
+	return *tx.r
 }
 
 // Value gives you access to the actual secret value stored inside Text.
-func (s Text) Value() string {
-	if s.v == nil {
+func (tx Text) Value() string {
+	if tx.v == nil {
 		return ""
 	}
-	return *s.v
+	return *tx.v
 }
 
 // MarshalText implements [encoding.TextMarshaler]. It marshals redact string into bytes rather than
 // the actual secret value.
-func (s Text) MarshalText() ([]byte, error) {
-	return []byte(*s.r), nil
+func (tx Text) MarshalText() ([]byte, error) {
+	return []byte(tx.String()), nil
 }
 
 // UnmarshalText implements [encoding.TextUnmarshaler]. It unmarshals b into receiver's new secret
 // value. If redact string is present then it is reused.
-func (s *Text) UnmarshalText(b []byte) error {
-	v := string(b)
+func (tx *Text) UnmarshalText(b []byte) error {
+	s := string(b)
 
 	// If the original redact is not nil then use it otherwise fallback to default.
-	if s.r != nil {
-		*s = New(v, CustomRedact(*s.r))
+	if tx.r != nil {
+		*tx = New(s, RedactHint(*tx.r))
 	} else {
-		*s = New(v)
+		*tx = New(s)
 	}
 	return nil
 }
 
 // Equals checks whether s2 has same secret string or not.
-func (s *Text) Equals(s2 Text) bool {
-	return *s.v == *s2.v
-}
-
-// Redacted option sets "[REDACTED]" as the redact hint.
-func Redacted(s *Text) {
-	*s.r = "[REDACTED]"
-}
-
-// FiveXs option sets "XXXXX" as the redact hint.
-func FiveXs(s *Text) {
-	*s.r = "XXXXX"
-}
-
-// CustomRedact option sets the value of r as the redact hint.
-func CustomRedact(r string) func(*Text) {
-	return func(s *Text) {
-		*s.r = r
-	}
+func (tx *Text) Equals(s2 Text) bool {
+	return *tx.v == *s2.v
 }