add u.TrimPrefix()

u/strings.go

@@ -43,3 +43,10 @@ func Capitalize(s string) string {
 	s = strings.ToLower(s)
 	return strings.ToUpper(s[0:1]) + s[1:]
 }
+
+// TrimPrefix is like strings.TrimPrefix but also returns a bool
+// indicating that the string was trimmed
+func TrimPrefix(s string, prefix string) (string, bool) {
+	s2 := strings.TrimPrefix(s, prefix)
+	return s2, len(s) != len(s2)
+}

u/strings_test.go

@@ -0,0 +1,22 @@
+package u
+
+import (
+	"testing"
+
+	"github.com/kjk/common/assert"
+)
+
+func TestTrimPrefix(t *testing.T) {
+	tests := []string{
+		"foo", "f", "oo",
+		"foo", "o", "foo",
+	}
+
+	n := len(tests)
+	for i := 0; i < n; i += 3 {
+		got, trimmed := TrimPrefix(tests[i], tests[i+1])
+		exp := tests[i+2]
+		assert.Equal(t, exp, got)
+		assert.Equal(t, trimmed, tests[i] != got, "%#v, %#v", tests[i], tests[i+1])
+	}
+}