What is React Strict Mode?

Sat, 26 Sep 2020 00:00:00 +0000

React Strict Mode is a tool, which comes with React, for detecting possible issues and problems in your application. Currently (Sept. 2020) Strict Mode detects if you have unsafe lifecycle methods, usage of legacy string ref API, usage of findDOMNode, detecting unexpected side effects or detecting usage of legacy context API.

So basically, using Strict Mode will help you detect if your app or libraries are using React APIs which are deprecated, unsafe in async code or have problems which might cause bugs. Strict Mode warnings are only displayed in development, so you don’t have to worry about them showing up in production. In the future, Strict Mode will likely add other warnings so even if you don’t have any now, it’s a good idea to keep using it.

Making API calls in React useEffect

Sat, 16 May 2020 09:33:01 +0000

useEffect is a hook added in React 16.8. It allows you to perform side effects in function components. This means you can update things outside of React based on your propsand state. Fetching data when the component state changes, changing the page <title> or connecting to a WebSocket server are all examples of side effects that can be done with useEffect.

As an example, we are going to build a component which fetches data from Cat Facts API and displays the received facts as a list. Finally we’ll add buttons to select the animal we want facts about.

Frontend on dev notes

What is React Strict Mode?

Making API calls in React useEffect