React’s setState method with prevState argument
I’m new to React, just have a question on setState method. Let’s say we have a component: so why we have to use prevState in the setState method? why can’t we just do:
reactjs
Trying to use fetch and pass in mode: no-cors
I can hit this endpoint, http://catfacts-api.appspot.com/api/facts?number=99 via Postman and it returns JSON Additionally I am using create-react-app and would like to avoid setting up any server config. In my client code I am trying to use fetch to do the same thing, but I get the error: No ‘Access-Control-Allow-Origin’ header is present on the requested … Read more
axios post request to send form data
You can post axios data by using FormData() like: And then add the fields to the form you want to send: If you are uploading images, you may want to use .append And then you can use axios post method (You can amend it accordingly) Related GitHub issue: Can’t get a .post with ‘Content-Type’: ‘multipart/form-data’ … Read more
how to download file in react js
Triggering browser download from front-end is not reliable. What you should do is, create an endpoint that when called, will provide the correct response headers, thus triggering the browser download. Front-end code can only do so much. The ‘download’ attribute for example, might just open the file in a new tab depending on the browser. … Read more
What does “isomorphic React” mean?
Isomorphic: “corresponding or similar in form or relations”. With regard to web apps, this means that the server is somehow similar to the client – in the sense that the server is capable of rendering as much as the client. In a way, isomorphic web apps are a return to the old paradigm where the … Read more
module.exports “Module is not defined”
RequireJS cannot load CommonJS modules as-is. However, there is a minimal modification you can make to them to load them. You have to wrap them in a define call like this: If you have a bunch of modules you need to convert, or if you are using a third-party library written in the CommonJS pattern … Read more
Scroll to the top of the page after render in react.js
Since the original solution was provided for very early version of react, here is an update:
forEach() in React JSX does not output any HTML
You need to pass an array of element to jsx. The problem is that forEach does not return anything (i.e it returns undefined). So it’s better to use map because map returns an array:
React.js – Can’t read property of undefined
The actual problem here is that the this context is not defined in your handleChangeOnMonth function. This is caused because of the way that javascript handles the contexts of functions, basically when calling functions if you are not calling them directly from the object, and they are not bound they will not have a defined … Read more
Warning: findDOMNode is deprecated in StrictMode. findDOMNode was passed an instance of Transition which is inside StrictMode
The setState call looks like it’s being written to the wrong place. Make sure it’s on the editTodo object: