fix: restore original editor size after resizing window in fullsize mode

Fixes #1278

Author: xdan

CHANGELOG.md

@@ -9,6 +9,12 @@
 > - :house: [Internal]
 > - :nail_care: [Polish]
 
+## 4.12.12
+
+#### :bug: Bug Fix
+
+- **Fullsize**: after entering fullsize mode, resizing the browser window, and then exiting fullsize, the editor kept the fullscreen width/height instead of returning to its original size. The `resize` handler (bound to `window.resize` when `globalFullSize` is on) re-saved the "original" size on every window resize, so it captured the fullscreen size. The original size is now stored only once when entering fullsize and restored on exit. Fixes [#1278](https://github.com/xdan/jodit/issues/1278).
+
 ## 4.12.11
 
 #### :bug: Bug Fix

src/plugins/fullsize/fullsize.test.js

@@ -5,6 +5,26 @@
  */
 
 describe('Fullsize plugin', function () {
+	describe('Resize window while in fullsize (#1278)', function () {
+		it('Should restore the original width after exiting fullsize', () => {
+			const editor = getJodit();
+
+			editor.container.style.width = '300px';
+			const originalWidth = editor.container.offsetWidth;
+
+			editor.toggleFullSize(true);
+
+			// The window is resized while the editor is in fullsize mode.
+			simulateEvent('resize', editor.ow);
+
+			editor.toggleFullSize(false);
+
+			expect(
+				Math.abs(editor.container.offsetWidth - originalWidth)
+			).is.below(3);
+		});
+	});
+
 	describe('Toggle fullsize', function () {
 		it('Should resize all boxes to first state', () => {
 			const editor = getJodit({

src/plugins/fullsize/fullsize.ts

@@ -41,19 +41,27 @@ export function fullsize(editor: IViewWithToolbar): void {
 			}
 
 			if (isEnabled) {
-				oldHeight = css(container, 'height', true) as number;
-				oldWidth = css(container, 'width', true) as number;
+				// Save the original size only once, when entering fullsize.
+				// Otherwise a window resize while in fullsize would overwrite it
+				// with the current (fullscreen) size, so exiting fullsize would
+				// restore the wrong dimensions (#1278).
+				if (!wasToggled) {
+					oldHeight = css(container, 'height', true) as number;
+					oldWidth = css(container, 'width', true) as number;
+					wasToggled = true;
+				}
+
 				css(container, {
 					height: editor.ow.innerHeight,
 					width: editor.ow.innerWidth
 				});
-
-				wasToggled = true;
 			} else if (wasToggled) {
 				css(container, {
 					height: oldHeight || 'auto',
 					width: oldWidth || 'auto'
 				});
+
+				wasToggled = false;
 			}
 		},
 		/**