Title normalizer is added. Fixes #45 (#59)

README.md

@@ -91,6 +91,7 @@ This package currently provides the following normalizers. They can be mixed wit
 
 - [lower](doc/normalizers/lower.md) maps all Unicode letters in the given value to their lower case.
 - [upper](doc/normalizers/upper.md) maps all Unicode letters in the given value to their upper case.
+- [title](doc/normalizers/title.md) maps the first letter of each word to their upper case.
 - [trim](doc/normalizers/trim.md) removes the whitespaces at the beginning and at the end of the given value.
 - [trim-left](doc/normalizers/trim_left.md) removes the whitespaces at the beginning of the given value.
 - [trim-right](doc/normalizers/trim_right.md) removes the whitespaces at the end of the given value.

checker.go

@@ -47,6 +47,7 @@ var makers = map[string]MakeFunc{
 	CheckerSame:         makeSame,
 	NormalizerLower:     makeLower,
 	NormalizerUpper:     makeUpper,
+	NormalizerTitle:     makeTitle,
 	NormalizerTrim:      makeTrim,
 	NormalizerTrimLeft:  makeTrimLeft,
 	NormalizerTrimRight: makeTrimRight,

doc/normalizers/lower.md

@@ -12,4 +12,6 @@ user := &User{
 }
 
 Check(user)
+
+fmt.Println(user.Username) // checker
 ```

doc/normalizers/title.md

@@ -0,0 +1,17 @@
+# Title Case Normalizer
+
+The ```title``` normalizer maps the first letter of each word to their upper case. It can be mixed with checkers and other normalizers when defining the validation steps for user data.
+
+```golang
+type Book struct {
+  Chapter string `checkers:"title"`
+}
+
+book := &Book{
+  Chapter: "THE Checker",
+}
+
+Check(book)
+
+fmt.Println(book.Chapter) // The Checker
+```

doc/normalizers/trim.md

@@ -12,4 +12,6 @@ user := &User{
 }
 
 Check(user)
+
+fmt.Println(user.Username) // CHECKER
 ```

doc/normalizers/trim_left.md

@@ -12,4 +12,6 @@ user := &User{
 }
 
 Check(user)
+
+fmt.Println(user.Username) // normalizer
 ```

doc/normalizers/trim_right.md

@@ -12,4 +12,6 @@ user := &User{
 }
 
 Check(user)
+
+fmt.Println(user.Username) // CHECKER
 ```

doc/normalizers/upper.md

@@ -11,5 +11,5 @@ user := &User{
   Username: "chECker",
 }
 
-Check(user)
+fmt.Println(user.Username) // CHECKER
 ```

title.go

@@ -0,0 +1,44 @@
+package checker
+
+import (
+	"reflect"
+	"strings"
+	"unicode"
+)
+
+// NormalizerTitle is the name of the normalizer.
+const NormalizerTitle = "title"
+
+// makeTitle makes a normalizer function for the title normalizer.
+func makeTitle(_ string) CheckFunc {
+	return normalizeTitle
+}
+
+// normalizeTitle maps the first letter of each word to their upper case.
+func normalizeTitle(value, _ reflect.Value) Result {
+	if value.Kind() != reflect.String {
+		panic("string expected")
+	}
+
+	var sb strings.Builder
+	begin := true
+
+	for _, c := range value.String() {
+		if unicode.IsLetter(c) {
+			if begin {
+				c = unicode.ToUpper(c)
+				begin = false
+			} else {
+				c = unicode.ToLower(c)
+			}
+		} else {
+			begin = true
+		}
+
+		sb.WriteRune(c)
+	}
+
+	value.SetString(sb.String())
+
+	return ResultValid
+}

title_test.go

@@ -0,0 +1,46 @@
+package checker
+
+import "testing"
+
+func TestNormalizeTitleNonString(t *testing.T) {
+	defer FailIfNoPanic(t)
+
+	type Book struct {
+		Chapter int `checkers:"title"`
+	}
+
+	book := &Book{}
+
+	Check(book)
+}
+
+func TestNormalizeTitleResultValid(t *testing.T) {
+	type Book struct {
+		Chapter string `checkers:"title"`
+	}
+
+	book := &Book{
+		Chapter: "THE Checker",
+	}
+
+	_, valid := Check(book)
+	if !valid {
+		t.Fail()
+	}
+}
+
+func TestNormalizeTitle(t *testing.T) {
+	type Book struct {
+		Chapter string `checkers:"title"`
+	}
+
+	book := &Book{
+		Chapter: "THE Checker",
+	}
+
+	Check(book)
+
+	if book.Chapter != "The Checker" {
+		t.Fail()
+	}
+}