✨ feat: strutil - add new func BeforeFirst, AfterFirst, AfterLast spl…

…it funcs

strutil/split.go

@@ -2,6 +2,38 @@ package strutil
 
 import "strings"
 
+// BeforeFirst get substring before first sep.
+func BeforeFirst(s, sep string) string {
+	if i := strings.Index(s, sep); i >= 0 {
+		return s[:i]
+	}
+	return s
+}
+
+// AfterFirst get substring after first sep.
+func AfterFirst(s, sep string) string {
+	if i := strings.Index(s, sep); i >= 0 {
+		return s[i+len(sep):]
+	}
+	return ""
+}
+
+// BeforeLast get substring before last sep.
+func BeforeLast(s, sep string) string {
+	if i := strings.LastIndex(s, sep); i >= 0 {
+		return s[:i]
+	}
+	return s
+}
+
+// AfterLast get substring after last sep.
+func AfterLast(s, sep string) string {
+	if i := strings.LastIndex(s, sep); i >= 0 {
+		return s[i+len(sep):]
+	}
+	return ""
+}
+
 /*************************************************************
  * String split operation
  *************************************************************/

strutil/split_test.go

@@ -8,6 +8,28 @@ import (
 	"github.com/gookit/goutil/testutil/assert"
 )
 
+func TestBeforeAfter(t *testing.T) {
+	// BeforeFirst
+	assert.Eq(t, "abc", strutil.BeforeFirst("abc", ":"))
+	assert.Eq(t, "abc", strutil.BeforeFirst("abc:123", ":"))
+	assert.Eq(t, "abc", strutil.BeforeFirst("abc:123:456", ":"))
+
+	// AfterFirst
+	assert.Eq(t, "", strutil.AfterFirst("abc", ":"))
+	assert.Eq(t, "123", strutil.AfterFirst("abc:123", ":"))
+	assert.Eq(t, "123:456", strutil.AfterFirst("abc:123:456", ":"))
+
+	// BeforeLast
+	assert.Eq(t, "abc", strutil.BeforeLast("abc", ":"))
+	assert.Eq(t, "abc", strutil.BeforeLast("abc:123", ":"))
+	assert.Eq(t, "abc:123", strutil.BeforeLast("abc:123:456", ":"))
+
+	// AfterLast
+	assert.Eq(t, "", strutil.AfterLast("abc", ":"))
+	assert.Eq(t, "123", strutil.AfterLast("abc:123", ":"))
+	assert.Eq(t, "456", strutil.AfterLast("abc:123:456", ":"))
+}
+
 func TestCut(t *testing.T) {
 	str := "hi,inhere"