What does 'Only a ReactOwner can have refs.' mean?

Question

I have a simple react component with a form in it:

var AddAppts = React.createClass({
    handleClick:          


        

Answer 1

For me the reason for the same problem was that I've imported the ReactDom globally, as a property of the window object, like this:

import ReactDOM from 'react-dom'
window.ReactDOM = ReactDOM

removing window.ReactDOM = ReactDOM fixed the problem.

Answer 2

This is FYI for people using react and redux-devtools who are getting OP's message. Your structure looks like

project
  client
  node_modules
    react
    redux-devtools
      node_modules
        react

The code in client will require the first react module; that in redux-devtools will require the other react. The react module keeps state and assumes it has all the state.

You get the OP's message because your state is split between the 2 react modules. This situation is what I believe @asbjornenge refers to.

I was bundling the client code with webpack, so I used that to handle the issue. You can force all require and import to always use the first react by adding the following to webpack.config.js

module.exports = {
  ...
  resolve: {
    alias: {
      'react': path.join(__dirname, 'node_modules', 'react')
    },
    extensions: ['', '.js']
  },
  ...
);

I have not looked into what I would need to do if the situation occurred with unbundled code running on node.

Answer 3

Just in case. Be aware of the React module name you are using (it is case-sensitive). I've got the same error when by coincidence I tried to require React dependency with different names in two separate modules.

//module1.js
var React = require('react');
...

//module2.js
var React = require('React');
....

It works and even renders something but the Only a ReactOwner can have refs... error appears.

Answer 4

I saw this error while developing a react module that was linked to a test project using npm link. Switching to a regular dependency solved the problem.

It seems that React doesn't like npm link.

Answer 5

There is another situation.

I set the React as external library in the webpack.config.js and import react.js from cdnjs.

externals: {
  'react': 'React'
}

When I using an ui library depend on React,such as material-ui,react-bootstrap,this issue occurred.

Answer 6

Instead of

<input ref="title"></input>

Try this

<input ref={(title) => this.title = title}></input>