issue #33: Add flag for human readable size for each file/folder

cmd/flag.go

@@ -12,4 +12,5 @@ func FlagDefinition(cmd *cobra.Command, flags *module.Flags) {
 	cmd.PersistentFlags().BoolVarP(&flags.ShowHidden, "all", "a", false, "List all files and directories")
 	cmd.PersistentFlags().BoolVarP(&flags.ShowTreeView, "tree", "t", false, "Tree view of the directory")
 	cmd.PersistentFlags().BoolVarP(&flags.HideIcon, "icon", "i", false, "Disable icons (Enabled by default)")
+	cmd.PersistentFlags().BoolVarP(&flags.ShowReadableSize, "readable", "r", false, "Show human-readable size for each file and directory")
 }

cmd/root_test.go

@@ -52,6 +52,26 @@ func TestRootCmd_ValidPathWithFlags(t *testing.T) {
 	}
 }
 
+func TestRootCmd_ReadableFlag(t *testing.T) {
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "main.go"), []byte("package main"), 0o644); err != nil {
+		t.Fatalf("WriteFile() error = %v", err)
+	}
+
+	output := captureStdout(t, func() {
+		cmd := newRootCmd()
+		cmd.SetArgs([]string{"-r", "--icon", dir})
+
+		if err := cmd.Execute(); err != nil {
+			t.Fatalf("Execute() error = %v, want nil", err)
+		}
+	})
+
+	if !strings.Contains(output, "main.go (12 B)") {
+		t.Fatalf("Execute() output = %q, want readable file size", output)
+	}
+}
+
 func captureStdout(t *testing.T, run func()) string {
 	t.Helper()
 

module/types.go

@@ -3,9 +3,10 @@ package module
 
 // Flags struct - represents flags for the application.
 type Flags struct {
-	ShowHidden   bool
-	ShowTreeView bool
-	HideIcon     bool
+	ShowHidden       bool
+	ShowTreeView     bool
+	HideIcon         bool
+	ShowReadableSize bool
 }
 
 // Options struct - Contains configuration options for directory listing.

service/service.go

@@ -82,12 +82,7 @@ func listDirectory(options module.Options, output io.Writer) (fileCount, dirCoun
 				fileCount++
 			}
 
-			var formatted string
-			if !options.Flags.HideIcon {
-				formatted = printWithIconAndPrefix("", file)
-			} else {
-				formatted = printFilesAndFolderWithoutIcons("", file)
-			}
+			formatted := formatFileWithOptions("", file, options.Flags)
 
 			entries = append(entries, formatted)
 
@@ -152,7 +147,7 @@ func printFilesAndDirectoriesTreeFormat(files []os.FileInfo, options module.Opti
 		isLast := i == lastVisibleIndex
 		prefix, childIndent := calculateIndent(indent, isLast)
 
-		if err := printFileWithPrefix(output, prefix, file, options.Flags.HideIcon); err != nil {
+		if err := printFileWithPrefix(output, prefix, file, options.Flags); err != nil {
 			return 0, 0, err
 		}
 
@@ -185,14 +180,24 @@ func calculateIndent(indent string, isLast bool) (prefix, childIndent string) {
 }
 
 // printFileWithPrefix prints the file with the given prefix and icon settings
-func printFileWithPrefix(output io.Writer, prefix string, file os.FileInfo, hideIcon bool) error {
-	if hideIcon {
-		_, err := fmt.Fprintln(output, printFilesAndFolderWithoutIcons(prefix, file))
-		return err
+func printFileWithPrefix(output io.Writer, prefix string, file os.FileInfo, flags module.Flags) error {
+	_, err := fmt.Fprintln(output, formatFileWithOptions(prefix, file, flags))
+	return err
+}
+
+func formatFileWithOptions(prefix string, file os.FileInfo, flags module.Flags) string {
+	var formatted string
+	if flags.HideIcon {
+		formatted = printFilesAndFolderWithoutIcons(prefix, file)
+	} else {
+		formatted = printWithIconAndPrefix(prefix, file)
 	}
 
-	_, err := fmt.Fprintln(output, printWithIconAndPrefix(prefix, file))
-	return err
+	if flags.ShowReadableSize {
+		formatted = appendReadableSize(formatted, file.Size())
+	}
+
+	return formatted
 }
 
 // processDirectory recursively processes a subdirectory

service/service_test.go

@@ -45,6 +45,12 @@ func TestDispatcher_ListDirectory(t *testing.T) {
 			flags:        module.Flags{HideIcon: true, ShowHidden: true},
 			wantContains: []string{".", ".hidden", "alpha.go", "subpkg", "1 directories, 2 files"},
 		},
+		{
+			name:         "shows readable file and directory sizes",
+			flags:        module.Flags{HideIcon: true, ShowReadableSize: true},
+			wantContains: []string{"alpha.go (12 B)", "subpkg (", "1 directories, 1 files"},
+			wantMissing:  []string{".hidden"},
+		},
 	}
 
 	for _, tt := range tests {
@@ -55,7 +61,7 @@ func TestDispatcher_ListDirectory(t *testing.T) {
 				t.Fatalf("dispatcher() error = %v, want nil", err)
 			}
 
-			got := output.String()
+			got := stripANSI(output.String())
 			for _, want := range tt.wantContains {
 				if !strings.Contains(got, want) {
 					t.Fatalf("dispatcher() output = %q, want to contain %q", got, want)
@@ -80,22 +86,45 @@ func TestDispatcher_TreeDirectory(t *testing.T) {
 	err := dispatcher(module.Options{
 		Directory: dir,
 		Flags: module.Flags{
-			HideIcon:     true,
-			ShowTreeView: true,
+			HideIcon:         true,
+			ShowTreeView:     true,
+			ShowReadableSize: true,
 		},
 	}, &output)
 	if err != nil {
 		t.Fatalf("dispatcher() error = %v, want nil", err)
 	}
 
-	got := output.String()
-	for _, want := range []string{"└── ", "subpkg", "nested.go", "1 directories, 2 files"} {
+	got := stripANSI(output.String())
+	for _, want := range []string{"└── ", "subpkg (", "nested.go (14 B)", "1 directories, 2 files"} {
 		if !strings.Contains(got, want) {
 			t.Fatalf("dispatcher() output = %q, want to contain %q", got, want)
 		}
 	}
 }
 
+func TestHumanReadableSize(t *testing.T) {
+	tests := []struct {
+		name string
+		size int64
+		want string
+	}{
+		{name: "zero bytes", size: 0, want: "0 B"},
+		{name: "bytes", size: 42, want: "42 B"},
+		{name: "kilobytes", size: 2048, want: "2.0 KB"},
+		{name: "megabytes", size: 1536 * 1024, want: "1.5 MB"},
+		{name: "negative size", size: -1, want: "0 B"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := humanReadableSize(tt.size); got != tt.want {
+				t.Fatalf("humanReadableSize(%d) = %q, want %q", tt.size, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestReadDirectory_FilePath(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "regular.txt")
 	mustWriteFile(t, path, "content")

service/util.go

@@ -441,6 +441,29 @@ func printFilesAndFolderWithoutIcons(prefix string, file os.FileInfo) string {
 	return format
 }
 
+func appendReadableSize(formatted string, size int64) string {
+	return fmt.Sprintf("%s (%s)", formatted, humanReadableSize(size))
+}
+
+func humanReadableSize(size int64) string {
+	if size < 0 {
+		size = 0
+	}
+	if size < 1024 {
+		return fmt.Sprintf("%d B", size)
+	}
+
+	units := []string{"KB", "MB", "GB", "TB", "PB"}
+	value := float64(size)
+	unitIndex := -1
+	for value >= 1024 && unitIndex < len(units)-1 {
+		value /= 1024
+		unitIndex++
+	}
+
+	return fmt.Sprintf("%.1f %s", value, units[unitIndex])
+}
+
 // sortSlice func - sorts a slice of os.FileInfo objects alphabetically by file name.
 // It modifies the original slice in place.
 func sortSlice(files []os.FileInfo) {