From ca88687f3de2912ee0980d9942fcefc650cbb0d4 Mon Sep 17 00:00:00 2001
From: dudaodong <dudaodong@gmail.com>
Date: Sat, 22 Jan 2022 18:55:41 +0800
Subject: [PATCH] feat: add UpperFirst func

---
 strutil/string.go      | 12 ++++++++++++
 strutil/string_test.go | 11 +++++++++++
 2 files changed, 23 insertions(+)

diff --git a/strutil/string.go b/strutil/string.go
index f3b1094..268099d 100644
--- a/strutil/string.go
+++ b/strutil/string.go
@@ -54,6 +54,18 @@ func Capitalize(s string) string {
 	return string(out)
 }
 
+// UpperFirst converts the first character of string to upper case.
+func UpperFirst(s string) string {
+	if len(s) == 0 {
+		return ""
+	}
+
+	r, size := utf8.DecodeRuneInString(s)
+	r = unicode.ToUpper(r)
+
+	return string(r) + s[size:]
+}
+
 // LowerFirst converts the first character of string to lower case.
 func LowerFirst(s string) string {
 	if len(s) == 0 {
diff --git a/strutil/string_test.go b/strutil/string_test.go
index ac7e35c..16432b7 100644
--- a/strutil/string_test.go
+++ b/strutil/string_test.go
@@ -50,6 +50,17 @@ func TestSnakeCase(t *testing.T) {
 	assert.NotEqual("foo-bar", SnakeCase("foo_Bar"))
 }
 
+func TestUpperFirst(t *testing.T) {
+	assert := internal.NewAssert(t, "TestLowerFirst")
+
+	assert.Equal("Foo", UpperFirst("foo"))
+	assert.Equal("BAR", UpperFirst("bAR"))
+	assert.Equal("FOo", UpperFirst("FOo"))
+	assert.Equal("FOo大", UpperFirst("fOo大"))
+
+	assert.NotEqual("Bar", UpperFirst("BAR"))
+}
+
 func TestLowerFirst(t *testing.T) {
 	assert := internal.NewAssert(t, "TestLowerFirst")