docs: add comments for all functions

util/common/err.go

@@ -1,3 +1,4 @@
+// Package common provides common utility functions for error handling, formatting, and multi-error management.
 package common
 
 import (
@@ -7,16 +8,19 @@ import (
 	"github.com/mhsanaei/3x-ui/v2/logger"
 )
 
+// NewErrorf creates a new error with formatted message.
 func NewErrorf(format string, a ...any) error {
 	msg := fmt.Sprintf(format, a...)
 	return errors.New(msg)
 }
 
+// NewError creates a new error from the given arguments.
 func NewError(a ...any) error {
 	msg := fmt.Sprintln(a...)
 	return errors.New(msg)
 }
 
+// Recover handles panic recovery and logs the panic error if a message is provided.
 func Recover(msg string) any {
 	panicErr := recover()
 	if panicErr != nil {

util/common/format.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 )
 
+// FormatTraffic formats traffic bytes into human-readable units (B, KB, MB, GB, TB, PB).
 func FormatTraffic(trafficBytes int64) string {
 	units := []string{"B", "KB", "MB", "GB", "TB", "PB"}
 	unitIndex := 0

util/common/multi_error.go

@@ -4,8 +4,10 @@ import (
 	"strings"
 )
 
+// multiError represents a collection of errors.
 type multiError []error
 
+// Error returns a string representation of all errors joined with " | ".
 func (e multiError) Error() string {
 	var r strings.Builder
 	r.WriteString("multierr: ")
@@ -16,6 +18,7 @@ func (e multiError) Error() string {
 	return r.String()
 }
 
+// Combine combines multiple errors into a single error, filtering out nil errors.
 func Combine(maybeError ...error) error {
 	var errs multiError
 	for _, err := range maybeError {