Add strict option to ToTitle

Author: jdkato

internal/string.go

@@ -59,7 +59,13 @@ func CharAt(s string, i int) byte {
 
 // ToTitle returns a copy of the string m with its first Unicode letter mapped
 // to its title case.
-func ToTitle(m string) string {
+func ToTitle(m string, strict bool) string {
 	r, size := utf8.DecodeRuneInString(m)
-	return string(unicode.ToTitle(r)) + strings.ToLower(m[size:])
+
+	other := m[size:]
+	if strict {
+		other = strings.ToLower(other)
+	}
+
+	return string(unicode.ToTitle(r)) + other
 }

strcase/sentence.go

@@ -65,7 +65,7 @@ func (sc *SentenceConverter) Convert(s string) string {
 		if entry := sc.inVocab(token); entry != "" {
 			made = append(made, entry)
 		} else if i == 0 || sc.indicator(prev, i-1) {
-			made = append(made, internal.ToTitle(token))
+			made = append(made, internal.ToTitle(token, true))
 		} else {
 			made = append(made, strings.ToLower(token))
 		}

strcase/title.go

@@ -97,7 +97,8 @@ func (tc *TitleConverter) Convert(s string) string {
 			(internal.CharAt(t, pos+ext) != '-' || internal.CharAt(t, pos-1) == '-') {
 			return sm
 		}
-		return internal.ToTitle(m)
+
+		return internal.ToTitle(m, false)
 	})
 }