feat: add UpperFirst func

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 {

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")