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

Question

I have a simple react component with a form in it:
var AddAppts = React.createClass({
handleClick: function() {
var title = this.refs.title.getDOMNode().value;
....
var appt = {
heading: title
...
}
CalendarActions.addAppointment(appt);
},
render: function() {
return (
<div>
<label>Description</label>
<input ref="title"></input>
...
</div>
);
}
});
module.exports = AddAppts;
I am trying to render this component in another react component:
var AddAppt = require('./AddAppts');
render: function() {
return (
<div>
<AddAppt />
</div>
);
}
but I get this error:
Uncaught Error: Invariant Violation: addComponentAsRefTo(...): Only a ReactOwner can have refs. This usually means that you're trying to add a ref to a component that doesn't have an owner (that is, was not created inside of another component's `render` method). Try rendering this component inside of a new top-level component which will hold the ref.
I have googled it, but cannot figure out what I need to do to fix this issue.

Answer 1

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 2

I encountered this error when a component module I was using had it's own react dependency installed. So I was using multiple versions of React.
Make sure NOT to list react under dependencies in your package.json.
This is why we have peerDependencies ;-)

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

Rearranging the script resolved the issue.
Wrong.
<script src="./lib/react.js"></script>
<script src="./lib/react-dom.js"></script>
<script src="./lib/react-with-addons.js"></script>
Correct
<script src="./lib/react.js"></script>
<script src="./lib/react-with-addons.js"></script>
<script src="./lib/react-dom.js"></script>
Reference https://github.com/gcanti/tcomb-form/issues/107#issuecomment-150891680

Answer 5

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 6

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 7

am writing with my old pen. make sure in your project root package.json move react dependency as early as possible. still you are getting issue? & if you are using npm modules and grunt task, you can add below clean task to remove inner components react(duplicates).
clean: {
react : ['node_modules/**/react','!node_modules/react']
},

Answer 8

I saw this error after I moved my package.json file up a level, so I had 2 node_modules directories in my project (one in ./node_modules and another in ./web/node_modules). Removing the old directory fixed the problem.

Answer 9

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 10

Similar to this answer, I was seeing this error while using a separate module that I had been developing in a separate directory using yarn link.
The solution was to run yarn unlink module-name in my project's working directory. I then removed node_modules and ran yarn upgrade module-name and yarn for good measure.

Answer 11

Instead of
<input ref="title"></input>
Try this
<input ref={(title) => this.title = title}></input>

Answer 12

None of the given solutions worked for me, though they certainly helped show me where to look.
For some reason my project has two node_modules folders - one in the root directory and one a level up. I'm new to React so I don't know if this is normal or what. I'm just going with what Visual Studio gave me when I started a new project.
Anyway, I knew which module was causing the problem, and it happened to only exist in one of the node_modules folders.
I moved the problem module over to the other node_modules folder. Problem solved.