I had the same error time ago and it was generated by a component which was using ref tag, and there was some manual manipulation. A good practice to see these kind of errors is drawing your app flow and see when your are calling setState. Another thing I would change if I were you … Read more
React does not allow you to do an early return prior to other hooks. If a component executes fewer hooks than a previous render, you will get the following error: Invariant Violation: Rendered fewer hooks than expected. This may be caused by an accidental early return statement. React can’t tell the difference between an early … Read more
You need to have your function in the componentDidMount lifecycle since this is the function that is called when the DOM has loaded. Make use of refs to access the DOM element <input type=”submit” className=”nameInput” id=”name” value=”cp-dev1″ onClick={this.writeData} ref = “cpDev1″/> componentDidMount: function(){ var name = React.findDOMNode(this.refs.cpDev1).value; this.someOtherFunction(name); } See this answer for more info … Read more
According to the doc, you can just use a normal React element instead of a function inside <Provider />. As a result, simply change your code to <Provider store={store}> <App /> </Provider> I think this has changed since react@0.14.
CSS in JS (with pseudo classes & MQ support) There are lots of libs to write CSS with React that supports pseudo classes but all, if not all of them requires you to inline or write your CSS in JS Which I highly recommend CSS Modules (Write your CSS as normal, but in a better … Read more
Solution 1: Get the children type. It will return null if Child component returns null: const isChildNull = children => { return Boolean(children.type()=== null); }; Solution 2: Using ReactDOMServer.renderToStaticMarkup. It converts the jsx elements to string. If children returns null then renderToStaticMarkup will return an empty string: import ReactDOMServer from ‘react-dom/server’; const isChildNull = children … Read more
Pete’s answer is great. Backbone models are inherently mutative, which (while not a problem in itself) means that when rerendering, you won’t have the old version of the model to compare to. This makes it harder to do intelligent optimizations by defining shouldComponentUpdate methods in key places on your components. (You also lose out on … Read more
I have found the answer to my question. The key is to understand the purpose of the Virtual DOM. First we have to see what approach React takes to render the components. Different javascript frameworks take different approaches to detect changes in the data model and render them on the view. Consider AngularJS. When we … Read more
So the issue is that I think that the {…register(“name”}} line actually includes a ref property. You could console.log that out to verify; this is what I found to be true when using {…field} with the ControlledComponent. A very quick fix to get rid of the console error is to just, after the line with … Read more
The most obvious difference is the syntax. A functional component is just a plain JavaScript function which accepts props as an argument and returns a React element. A class component requires you to extend from React.Component and create a render function which returns a React element. This requires more code but will also give you … Read more