diff --git a/area.js b/area.js
index 0a65586..0b3ad26 100644
--- a/area.js
+++ b/area.js
@@ -20,7 +20,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-const ByteArray = imports.byteArray;
 const Cairo = imports.cairo;
 const Clutter = imports.gi.Clutter;
 const Gio = imports.gi.Gio;
@@ -57,43 +56,6 @@ var ToolNames = Object.assign({}, ShapeNames, ManipulationNames);
 
 var FontGenericNames = {  0: 'Theme', 1: 'Sans-Serif', 2: 'Serif', 3: 'Monospace', 4: 'Cursive', 5: 'Fantasy' };
 
-var getDateString = function() {
-    let date = GLib.DateTime.new_now_local();
-    return `${date.format("%F")} ${date.format("%X")}`;
-};
-
-var getJsonFiles = function() {
-    let directory = Gio.File.new_for_path(GLib.build_filenamev([GLib.get_user_data_dir(), Me.metadata['data-dir']]));
-    
-    let enumerator;
-    try {
-        enumerator = directory.enumerate_children('standard::name,standard::display-name,standard::content-type,time::modified', Gio.FileQueryInfoFlags.NONE, null);
-    } catch(e) {
-        return [];
-    }
-    
-    let jsonFiles = [];
-    let fileInfo = enumerator.next_file(null);
-    while (fileInfo) {
-        if (fileInfo.get_content_type().indexOf('json') != -1 && fileInfo.get_name() != `${Me.metadata['persistent-file-name']}.json`) {
-            let file = enumerator.get_child(fileInfo);
-            jsonFiles.push({ name: fileInfo.get_name().slice(0, -5),
-                             displayName: fileInfo.get_display_name().slice(0, -5),
-                             // fileInfo.get_modification_date_time: Gio 2.62+
-                             modificationUnixTime: fileInfo.get_attribute_uint64('time::modified'),
-                             delete: () => file.delete(null) });
-        }
-        fileInfo = enumerator.next_file(null);
-    }
-    enumerator.close(null);
-    
-    jsonFiles.sort((a, b) => {
-        return b.modificationUnixTime - a.modificationUnixTime;
-    });
-    
-    return jsonFiles;
-};
-
 // DrawingArea is the widget in which we draw, thanks to Cairo.
 // It creates and manages a DrawingElement for each "brushstroke".
 // It handles pointer/mouse/(touch?) events and some keyboard events.
@@ -1092,7 +1054,7 @@ var DrawingArea = new Lang.Class({
         }
         content += "\n</svg>";
         
-        let filename = `${Me.metadata['svg-file-name']} ${getDateString()}.svg`;
+        let filename = `${Me.metadata['svg-file-name']} ${Files.getDateString()}.svg`;
         let dir = GLib.get_user_special_dir(GLib.UserDirectory.DIRECTORY_PICTURES);
         let path = GLib.build_filenamev([dir, filename]);
         if (GLib.file_test(path, GLib.FileTest.EXISTS))
@@ -1120,34 +1082,25 @@ var DrawingArea = new Lang.Class({
             this._stopDrawing();
         }
         
-        let dir = GLib.build_filenamev([GLib.get_user_data_dir(), Me.metadata['data-dir']]);
-        if (!GLib.file_test(dir, GLib.FileTest.EXISTS))
-            GLib.mkdir_with_parents(dir, 0o700);
-        let path = GLib.build_filenamev([dir, `${name}.json`]);
-        
+        let json = new Files.Json({ name });
         let oldContents;
         
         if (name == Me.metadata['persistent-file-name']) {
-            if (GLib.file_test(path, GLib.FileTest.EXISTS)) {
-                oldContents = GLib.file_get_contents(path)[1];
-                if (oldContents instanceof Uint8Array)
-                    oldContents = ByteArray.toString(oldContents);
-            }
-            
+            let oldContents = json.contents;
             // do not create a file to write just an empty array
             if (!oldContents && this.elements.length == 0)
                 return;
         }
         
         // do not use "content = JSON.stringify(this.elements, null, 2);", neither "content = JSON.stringify(this.elements);"
-        // because of compromise between disk usage and human readability
+        // do compromise between disk usage and human readability
         let contents = `[\n  ` + new Array(...this.elements.map(element => JSON.stringify(element))).join(`,\n\n  `) + `\n]`;
         
         if (name == Me.metadata['persistent-file-name'] && contents == oldContents)
             return;
         
         GLib.idle_add(GLib.PRIORITY_DEFAULT_IDLE, () => {
-            GLib.file_set_contents(path, contents);
+            json.contents = contents;
             if (notify)
                 this.emit('show-osd', 'document-save-symbolic', name, "", -1, false);
             if (name != Me.metadata['persistent-file-name']) {
@@ -1162,7 +1115,7 @@ var DrawingArea = new Lang.Class({
     },
     
     saveAsJson: function() {
-        this._saveAsJson(getDateString(), true);
+        this._saveAsJson(Files.getDateString(), true);
     },
     
     savePersistent: function() {
@@ -1188,16 +1141,10 @@ var DrawingArea = new Lang.Class({
         this.elements = [];
         this.currentElement = null;
         
-        let dir = GLib.get_user_data_dir();
-        let path = GLib.build_filenamev([dir, Me.metadata['data-dir'], `${name}.json`]);
+        let contents = (new Files.Json({ name })).contents;
+        if (!contents)
+            return;
         
-        if (!GLib.file_test(path, GLib.FileTest.EXISTS))
-            return;
-        let [success, contents] = GLib.file_get_contents(path);
-        if (!success)
-            return;
-        if (contents instanceof Uint8Array)
-            contents = ByteArray.toString(contents);
         this.elements.push(...JSON.parse(contents).map(object => {
             if (object.image)
                 object.image = new Files.Image(object.image);
@@ -1222,7 +1169,7 @@ var DrawingArea = new Lang.Class({
     },
     
     loadNextJson: function() {
-        let names = getJsonFiles().map(file => file.name);
+        let names = Files.getJsons().map(json => json.name);
         
         if (!names.length)
             return;
@@ -1232,7 +1179,7 @@ var DrawingArea = new Lang.Class({
     },
     
     loadPreviousJson: function() {
-        let names = getJsonFiles().map(file => file.name);
+        let names = Files.getJsons().map(json => json.name);
         
         if (!names.length)
             return;
diff --git a/files.js b/files.js
index ec55aa7..c7bef27 100644
--- a/files.js
+++ b/files.js
@@ -20,6 +20,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+const ByteArray = imports.byteArray;
 const Gdk = imports.gi.Gdk;
 const GdkPixbuf = imports.gi.GdkPixbuf;
 const Gio = imports.gi.Gio;
@@ -31,6 +32,7 @@ const Me = ExtensionUtils.getCurrentExtension();
 const EXAMPLE_IMAGES = Me.dir.get_child('data').get_child('images');
 const USER_IMAGES = Gio.File.new_for_path(GLib.build_filenamev([GLib.get_user_data_dir(), Me.metadata['data-dir'], 'images']));
 
+// wrapper around an image file
 var Image = new Lang.Class({
     Name: 'DrawOnYourScreenImage',
     
@@ -130,3 +132,92 @@ var getImages = function() {
     
     return images;
 };
+
+// wrapper around a json file
+var Json = new Lang.Class({
+    Name: 'DrawOnYourScreenJson',
+    
+    _init: function(params) {
+        for (let key in params)
+            this[key] = params[key];
+    },
+    
+    toString: function() {
+        return this.displayName || this.name;
+    },
+    
+    delete: function() {
+        this.file.delete(null);
+    },
+    
+    get file() {
+        if (!this._file && this.name) 
+            this._file = Gio.File.new_for_path(GLib.build_filenamev([GLib.get_user_data_dir(), Me.metadata['data-dir'], `${this.name}.json`]));
+        
+        return this._file || null;
+    },
+    
+    set file(file) {
+        this._file = file;
+    },
+    
+    get contents() {
+        let success_, contents;
+        try {
+            [success_, contents] = this.file.load_contents(null);
+            if (contents instanceof Uint8Array)
+                contents = ByteArray.toString(contents);
+        } catch(e) {
+            return null;
+        }
+        return contents;
+    },
+    
+    set contents(contents) {
+        try {
+            this.file.replace_contents(contents, null, false, Gio.FileCreateFlags.NONE, null);
+        } catch(e) {
+            this.file.get_parent().make_directory_with_parents(null);
+            this.file.replace_contents(contents, null, false, Gio.FileCreateFlags.NONE, null);
+        }
+    }
+});
+
+var getJsons = function() {
+    let directory = Gio.File.new_for_path(GLib.build_filenamev([GLib.get_user_data_dir(), Me.metadata['data-dir']]));
+    
+    let enumerator;
+    try {
+        enumerator = directory.enumerate_children('standard::name,standard::display-name,standard::content-type,time::modified', Gio.FileQueryInfoFlags.NONE, null);
+    } catch(e) {
+        return [];
+    }
+    
+    let jsons = [];
+    let fileInfo = enumerator.next_file(null);
+    while (fileInfo) {
+        if (fileInfo.get_content_type().indexOf('json') != -1 && fileInfo.get_name() != `${Me.metadata['persistent-file-name']}.json`) {
+            let file = enumerator.get_child(fileInfo);
+            jsons.push(new Json({
+                file,
+                name: fileInfo.get_name().slice(0, -5),
+                displayName: fileInfo.get_display_name().slice(0, -5),
+                // fileInfo.get_modification_date_time: Gio 2.62+
+                modificationUnixTime: fileInfo.get_attribute_uint64('time::modified')
+            }));
+        }
+        fileInfo = enumerator.next_file(null);
+    }
+    enumerator.close(null);
+    
+    jsons.sort((a, b) => {
+        return b.modificationUnixTime - a.modificationUnixTime;
+    });
+    
+    return jsons;
+};
+
+var getDateString = function() {
+    let date = GLib.DateTime.new_now_local();
+    return `${date.format("%F")} ${date.format("%X")}`;
+};
diff --git a/menu.js b/menu.js
index a8ccba0..0a09f03 100644
--- a/menu.js
+++ b/menu.js
@@ -39,6 +39,7 @@ const Me = ExtensionUtils.getCurrentExtension();
 const Area = Me.imports.area;
 const Elements = Me.imports.elements;
 const Extension = Me.imports.extension;
+const Files = Me.imports.files;
 const _ = imports.gettext.domain(Me.metadata['gettext-domain']).gettext;
 
 const GS_VERSION = Config.PACKAGE_VERSION;
@@ -438,10 +439,10 @@ var DrawingMenu = new Lang.Class({
     
     _populateOpenDrawingSubMenu: function() {
         this.openDrawingSubMenu.removeAll();
-        let jsonFiles = Area.getJsonFiles();
-        jsonFiles.forEach(file => {
-            let item = this.openDrawingSubMenu.addAction(`<i>${file.displayName}</i>`, () => {
-                this.area.loadJson(file.name);
+        let jsons = Files.getJsons();
+        jsons.forEach(json => {
+            let item = this.openDrawingSubMenu.addAction(`<i>${String(json)}</i>`, () => {
+                this.area.loadJson(json.name);
                 this._updateDrawingNameMenuItem();
                 this._updateSaveDrawingSubMenuItemSensitivity();
             });
@@ -460,7 +461,7 @@ var DrawingMenu = new Lang.Class({
             getActor(item).add_child(deleteButton);
             
             deleteButton.connect('clicked', () => {
-                file.delete();
+                json.delete();
                 item.destroy();
             });
         });
@@ -494,7 +495,7 @@ var DrawingMenu = new Lang.Class({
     
     _populateSaveDrawingSubMenu: function() {
         this.saveDrawingSubMenu.removeAll();
-        let saveEntry = new DrawingMenuEntry({ initialTextGetter: Area.getDateString,
+        let saveEntry = new DrawingMenuEntry({ initialTextGetter: Files.getDateString,
                                                 entryActivateCallback: (text) => {
                                                     this.area.saveAsJsonWithName(text);
                                                     this.saveDrawingSubMenu.toggle();