Detect non-window element resize

.babelrc

@@ -1,6 +1,14 @@
 {
   "env": {
     "commonjs": {
+      "ignore": [
+        "*.jest.js",
+        "*.e2e.js",
+        "*.example.js",
+        "source/demo",
+        "source/jest-*.js",
+        "source/TestUtils.js"
+      ],
       "plugins": [
         "transform-runtime",
         "flow-react-proptypes",
@@ -51,6 +59,14 @@
       ]
     },
     "es": {
+      "ignore": [
+        "*.jest.js",
+        "*.e2e.js",
+        "*.example.js",
+        "source/demo",
+        "source/jest-*.js",
+        "source/TestUtils.js"
+      ],
       "plugins": [
         "transform-runtime",
         "flow-react-proptypes",

package.json

@@ -10,12 +10,12 @@
   "jsnext:main": "dist/es/index.js",
   "license": "MIT",
   "scripts": {
-    "build:types": "flow-copy-source --ignore \"**/*.{jest,example}.js\" source/WindowScroller dist/es/WindowScroller",
+    "build:types": "flow-copy-source --ignore \"**/*.{jest,e2e,example}.js\" source/WindowScroller dist/es/WindowScroller",
     "build": "npm run build:commonjs && npm run build:css && npm run build:es && npm run build:demo && npm run build:umd",
-    "build:commonjs": "npm run clean:commonjs && cross-env NODE_ENV=production cross-env BABEL_ENV=commonjs babel source --out-dir dist/commonjs --ignore *.example.js,*.jest.js,source/demo/",
+    "build:commonjs": "npm run clean:commonjs && cross-env NODE_ENV=production cross-env BABEL_ENV=commonjs babel source --out-dir dist/commonjs",
     "build:css": "postcss source/styles.css -o styles.css --use autoprefixer",
     "build:demo": "npm run clean:demo && cross-env NODE_ENV=production webpack --config webpack.config.demo.js -p --bail",
-    "build:es": "npm run clean:es && npm run build:types && cross-env NODE_ENV=production cross-env BABEL_ENV=es babel source --out-dir dist/es --ignore *.example.js,*.jest.js,source/demo/",
+    "build:es": "npm run clean:es && npm run build:types && cross-env NODE_ENV=production cross-env BABEL_ENV=es babel source --out-dir dist/es",
     "build:umd": "npm run clean:umd && cross-env NODE_ENV=production webpack --config webpack.config.umd.js --bail",
     "check-all": "yarn prettier && yarn lint && yarn flow",
     "ci-check": "yarn prettier:diff && yarn lint && yarn flow",

source/WindowScroller/WindowScroller.e2e.js

@@ -111,3 +111,55 @@ test('save position after resize and then scroll in container', async () => {
     [{width: 400, height: 600}],
   ]);
 });
+
+test('react on container resize without window changing', async () => {
+  const page = await bootstrap();
+  const resizeFn = jest.fn();
+  await page.exposeFunction('resizeFn', resizeFn);
+
+  await page.evaluate(() => {
+    const {render} = window.ReactDOM;
+    const {createElement} = window.React;
+    const {WindowScroller} = window.ReactVirtualized;
+
+    const wrapper = document.createElement('div');
+    wrapper.id = 'wrapper';
+    Object.assign(wrapper.style, {
+      width: '1000px',
+      height: '800px',
+      display: 'flex',
+    });
+    const container = document.createElement('div');
+    Object.assign(container.style, {
+      flex: '1',
+    });
+    wrapper.appendChild(container);
+    document.body.style.margin = 0;
+    document.body.appendChild(wrapper);
+
+    render(
+      createElement(
+        WindowScroller,
+        {scrollElement: container, onResize: window.resizeFn},
+        () => null,
+      ),
+      container,
+    );
+  });
+
+  await delay(100);
+
+  await page.$eval('#wrapper', el => {
+    el.style.width = '500px';
+    el.style.height = '700px';
+  });
+
+  await delay(100);
+
+  await page.close();
+
+  expect(resizeFn.mock.calls).toEqual([
+    [{width: 1000, height: 800}],
+    [{width: 500, height: 700}],
+  ]);
+});

source/WindowScroller/WindowScroller.js

@@ -12,6 +12,7 @@ import {
   getPositionOffset,
   getScrollOffset,
 } from './utils/dimensions';
+import createDetectElementResize from '../vendor/detectElementResize';
 
 type Props = {
   /**
@@ -57,6 +58,13 @@ type State = {
   scrollTop: number,
 };
 
+type ResizeHandler = (element: Element, onResize: () => void) => void;
+
+type DetectElementResize = {
+  addResizeListener: ResizeHandler,
+  removeResizeListener: ResizeHandler,
+};
+
 /**
  * Specifies the number of miliseconds during which to disable pointer events while a scroll is in progress.
  * This improves performance and makes scrolling smoother.
@@ -79,6 +87,7 @@ export default class WindowScroller extends React.PureComponent<Props, State> {
   _isMounted = false;
   _positionFromTop = 0;
   _positionFromLeft = 0;
+  _detectElementResize: DetectElementResize = createDetectElementResize();
 
   state = {
     ...getDimensions(this.props.scrollElement, this.props),
@@ -121,10 +130,9 @@ export default class WindowScroller extends React.PureComponent<Props, State> {
 
     if (scrollElement) {
       registerScrollListener(this, scrollElement);
+      this._registerResizeListener(scrollElement);
     }
 
-    window.addEventListener('resize', this._onResize, false);
-
     this._isMounted = true;
   }
 
@@ -141,14 +149,18 @@ export default class WindowScroller extends React.PureComponent<Props, State> {
 
       unregisterScrollListener(this, scrollElement);
       registerScrollListener(this, nextScrollElement);
+
+      this._unregisterResizeListener(scrollElement);
+      this._registerResizeListener(nextScrollElement);
     }
   }
 
   componentWillUnmount() {
-    if (this.props.scrollElement) {
-      unregisterScrollListener(this, this.props.scrollElement);
+    const scrollElement = this.props.scrollElement;
+    if (scrollElement) {
+      unregisterScrollListener(this, scrollElement);
+      this._unregisterResizeListener(scrollElement);
     }
-    window.removeEventListener('resize', this._onResize, false);
 
     this._isMounted = false;
   }
@@ -182,6 +194,22 @@ export default class WindowScroller extends React.PureComponent<Props, State> {
     }
   };
 
+  _registerResizeListener = element => {
+    if (element === window) {
+      window.addEventListener('resize', this._onResize, false);
+    } else {
+      this._detectElementResize.addResizeListener(element, this._onResize);
+    }
+  };
+
+  _unregisterResizeListener = element => {
+    if (element === window) {
+      window.removeEventListener('resize', this._onResize, false);
+    } else if (element) {
+      this._detectElementResize.removeResizeListener(element, this._onResize);
+    }
+  };
+
   _onResize = () => {
     this.updatePosition();
   };