Repros https://github.com/chingyawhao/material-ui-next-pickers/issues/20 using @material-ui/core 3.2.0 and material-ui-next-pickers 0.0.15 Simply use `npx create-react-app my-app --scripts-version=react-scripts-ts` and use the attached versions of the files.

App.tsx

import * as React from 'react';

import { MyComponent } from "src/MyComponent";

import logo from './logo.svg';

class App extends React.Component {
  public render() {
    return (
      <div className="App">
        <header className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h1 className="App-title">Welcome to React</h1>
        </header>
        <p className="App-intro">
          To get started, edit <code>src/App.tsx</code> and save to reload.
        </p>
        <MyComponent />
      </div>
    );
  }
}

export default App;

index.tsx

import { CssBaseline } from "@material-ui/core";
import deepPurple from "@material-ui/core/colors/deepPurple";
import { createMuiTheme, MuiThemeProvider } from '@material-ui/core/styles';
import * as React from 'react';
import * as ReactDOM from 'react-dom';

import App from './App';
import registerServiceWorker from './registerServiceWorker';

const theme = createMuiTheme({
  palette: {
    primary: deepPurple,
  },
});

ReactDOM.render(
  <MuiThemeProvider theme={theme}>
    <CssBaseline />
    <App />
  </MuiThemeProvider>,
  document.getElementById('root') as HTMLElement
);
registerServiceWorker();

MyComponent.tsx

import { DateFormatInput } from "material-ui-next-pickers";
import * as React from "react";

interface IMyComponentState {
    date: Date;
}

export class MyComponent extends React.Component<any, IMyComponentState> {
    constructor(props: any) {
        super(props);

        this.state = {
            "date": new Date(),
        };
    }

    public render(): JSX.Element {
        return (
            <DateFormatInput name='date-input' value={this.state.date} onChange={this.onChangeDate} />
        );
    }

    private onChangeDate = (newDate: Date): void => {
        this.setState({ "date": newDate });
    }
}