When should I use componentWillReceiveProps?

5 Answers. componentWillReceiveProps is required if you want to update the state values with new props values, this method will get called whenever any change happens to props values.

Similarly, you may ask, when should I use componentWillMount?

componentWillMount runs before initial rendering. But it is not advised to do any subscriptions and state setting in this method. If you want to some of that before rendering you can use the constructor of the component. componentDidMount() instead.

Additionally, is componentWillReceiveProps deprecated? The componentWillReceiveProps() method is being deprecated in future version of React (17). Many of us use this method day-to-day to check for incoming prop changes, store state, and to invoke side effects like logging or fetching data from a server.

Likewise, when should I use componentDidUpdate?

The componentDidUpdate is particularly useful when an operation needs to happen after the DOM is updated and the update queue is emptied. It's probably most useful on complex renders and state or DOM changes or when you need something to be the absolutely last thing to be executed.

When should I use componentDidMount vs componentWillMount?

componentDidMount() is only called once, on the client, compared to componentWillMount() which is called twice, once to the server and once on the client. It is called after the initial render when the client received data from the server and before the data is displayed in the browser.

35 Related Question Answers Found

What can I use instead of componentWillReceiveProps?

getDerivedStateFromProps is one of those newly introduced lifecycle method replacing componentWillReceiveProps , which has now become UNSAFE_componentWillReceiveProps . getDerivedStateFromProps is a static method which is invoked after a component is instantiated as well as when it receives new props.

Is componentWillMount deprecated?

componentWillMount is deprecated and will be removed in the next major version 0.54.

How many times does componentWillMount get called?

componentWillMount is called twice. #1646.

Why is componentWillReceiveProps deprecated?

But the getDerivedStateFromProps is an asynchronous hook won't require any additional render. Thus, componentWillReceiveProps is being deprecated in favor of the following reason: Use getDerivedStateFromProps. Or, use componentDidUpdate.

Why is componentDidMount called twice?

The main reason to put it in componentDidMount is so it doesn't run on the server, because server-side components never get mounted. This is important for universal rendering. Even if you're not doing this now, you might do this later, and being prepared for it is a best practice.

What are super props?

super() is used to call the parent constructor. super(props) would pass props to the parent constructor. From your example, super(props) would call the React. Component constructor passing in props as the argument.

What is a lifecycle method?

You can think of React lifecycle methods as the series of events that happen from the birth of a React component to its death. Every component in React goes through a lifecycle of events. I like to think of them as going through a cycle of birth, growth, and death.

Why is componentWillMount unsafe?

Async rendering will cause componentWillMount to trigger multiple rendering of your component tree. This makes it unsafe.

Can we setState in componentDidUpdate?

You may call setState() immediately in componentDidUpdate() but note that it must be wrapped in a condition like in the example above, or you'll cause an infinite loop. It would also cause an extra re-rendering which, while not visible to the user, can affect the component performance.

Why is getDerivedStateFromProps static?

The reason getDerivedStateFromProps is static is to discourage any side-effects during the render phase. For example, updating or using props on the instance. This isn't safe anymore with the upcoming async rendering. It is called when a component is created and each time it recieves a new props.

What is prevProps?

The prevState or prevProps are just the state or props before the component in question is re-rendered.

Why did you update?

Why did you update? why-did-you-update is a library that hooks into React and detects potentially unnecessary component renders. It detects when a component's render method is called despite its props not having changed.

Is componentDidMount called after render?

The componentDidMount() method

That is after the HTML from render has finished loading. It is called once in the component life cycle and it signals that the component and all its sub-components have rendered properly.

What is nextProps in react?

componentWillReceiveProps(nextProps)

What's great about React lifecycle components is that they are names really well. As you can guess from its name, this function will be called when a stream of new props arrive from the parent component.

Should component update in react?

Typical React dogma says that when a component receives new props, or new state, it should update. But our component is a little bit anxious and is going to ask permission first. Here's what we get — a shouldComponentUpdate method, called with nextProps as the first argument, and nextState is the second.

What are react hooks?

React Hooks are functions that let us hook into the React state and lifecycle features from function components. By this, we mean that hooks allow us to easily manipulate the state of our functional component without needing to convert them into class components.

Should I use shouldComponentUpdate?

As you know, deepEquals will be fast on small objects, and slow on heavily nested ones. So this approximation gives us a good rule of thumb: If the value returned by render is tiny but props is heavy, shouldComponentUpdate will likely do more harm than good.