Debugging a React component can be a pain.
There are many causes for “statePropsPrecalculationError”, for debugging see my post on Debugging React statePropsPrecalculationError post.
When you specifically have ” ‘state’ of undefined” the fix is simple:
Recently I ran into “statePropsPrecalculationError” alongside with the the console warning TypeError: Cannot read property ‘state’ of undefined(…)`.
This is super easy to fix, but not immediately obvious. Whenever you use `this.setState()` inside your component, you must define your initial state!
Just add a `getInitialState()` definition!
const MyComponent = React.createClass({
getInitialState() {
return {
isOpen: false
};
},
toggleOpen() {
this.setState({isOpen: !this.state.isOpen});
},
render() {
return (
);
}
});