Add Access The Latest Lifecycle Methods In An Old App as a react til

react/access-the-latest-lifecycle-methods-in-an-old-app.md

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+# Access The Latest Lifecycle Methods In An Old App
+
+With the release of React 16.3 we have access to some new lifecycle methods
+and are in the first phase of what will eventually result in the deprecation
+and removal of `componentWillMount`, `componentWillReceiveProps`, and
+`componentWillUpdate`.
+
+You may not be ready to move your project to React 16.3, but that doesn't
+mean you can't start migrating your lifecycle methods now. We'll need a
+polyfill --
+[react-lifecycles-compat](https://github.com/reactjs/react-lifecycles-compat).
+
+```javascript
+import React from 'react';
+import { pollyfill } from 'react-lifecycles-compat';
+
+class MyComponent extends React.Component {
+  static getDerivedStateFromProps(nextProps, prevState) {
+    // ...
+  }
+
+  render() { ... }
+}
+polyfill(MyComponent)
+
+export default MyComponent;
+```
+
+For any of our class components for which we'd like to start using the new
+lifecycle methods, we just need to import the polyfill function and then
+transform the class component with the polyfill before exporting it.
+
+[source](https://reactjs.org/blog/2018/03/27/update-on-async-rendering.html#open-source-project-maintainers)