TypeError : React object is undefined on createElement

问题

I am new to React and Material UI and I am attempting to create an AppBar with Tabs as children. My current implementation looks like this:

import {React, PropTypes, Component} from 'react';
import TodoTextInput from './TodoTextInput';
import injectTapEventPlugin from 'react-tap-event-plugin';
import baseTheme from 'material-ui/styles/baseThemes/lightBaseTheme'
import getMuiTheme from 'material-ui/styles/getMuiTheme'
import {Tabs, Tab} from 'material-ui/Tabs';
import {AppBar} from 'material-ui/AppBar';

const styles = {
  headline: {
    fontSize: 24,
    paddingTop: 16,
    marginBottom: 12,
    fontWeight: 400
  }
};

function handleActive(tab) {
  alert(`A tab with this route property ${tab.props['data-route']} was activated.`);
}
const defaultStyle = {
  marginLeft: 20
};

class Header extends Component {
  render() {
    return (
      <header className="header">
      <AppBar title="TEST" />
        <Tabs>
          <Tab label="Tab 1" >
            <div>

            </div>
          </Tab>
          <Tab label="Tab 2" >
            <div>

            </div>
          </Tab>
          <Tab label="Tab 3" >
            <div>

            </div>
          </Tab>
          <Tab label="Tab 4" >
            <div>

            </div>
          </Tab>
        </Tabs>
        {children}
      </header>
    );
  }
}

module.exports = Header;

I'm getting an error that states:

TypeError: undefined is not an object (evaluating '_react.React.createElement')

I am unsure on how to fix this problem. Please help!

回答1:

You are importing React wrong, you're close though. Change it to

import React, { PropTypes, Component } from 'react';

Think of React as the parent and the others as children. You could also just import React and access the other with React.PropTypes and React.Component.

来源：https://stackoverflow.com/questions/40600763/typeerror-react-object-is-undefined-on-createelement

标签

javascript

reactjs

tabs

material-ui

appbar