Question: How Does A Pure Component Work?

What does 3 dots mean in react?

Spread OperatorsThree dots …

represents Spread Operators or Rest Parameters, It allows an array expression or string or anything which can be iterating to be expanded in places where zero or more arguments for function calls or elements for array are expected..

What are the two elements of a pure function?

In computer programming, a pure function is a function that has the following properties: Its return value is the same for the same arguments (no variation with local static variables, non-local variables, mutable reference arguments or input streams from I/O devices).

When use pure react component?

PureComponent Is Primarily Used for Performance Optimization. As outlined in the React docs: If your React component’s render() function renders the same result given the same props and state, you can use React. PureComponent for a performance boost in some cases.

When would you not use react pure component?

2 Answers. You should use it when a component could re-render even if it had the same props and state. An example of this is when a parent component had to re-render but the child component props and state didn’t change. The child component could benefit from PureComponent because it really didn’t need to re-render.

What is a pure function react?

What are pure functions? Pure functions take an input value (a parameter or argument) and depending on that input, produce an output value, that’s all. They do one thing only, but they do it well. It should be that whenever you give a pure function the same input it will return the same output every single time.

What is pure component in react with example?

Pure components A React component can be considered pure if it renders the same output for the same state and props. For class components like this, React provides the PureComponent base class. Class components that extend the React. PureComponent class are treated as pure components.

Are react hooks pure functions?

It is a pure function and as such, side effect free. … In React, this generally meant that side effects are added to stateful class components. These class components, often called container components, execute the side effects and pass props down to these pure stateless component functions.

What is the difference between a pure component and a regular component?

PureComponent is exactly the same as Component except that it handles the shouldComponentUpdate method for you . When props or state changes, PureComponent will do a shallow comparison on both props and state. Component on the other hand won’t compare current props and state to next out of the box.

How do you create a functional component in react?

We can create a functional component to React by writing a JavaScript function. These functions may or may not receive data as parameters. In the functional Components, the return value is the JSX code to render to the DOM tree. Example: Program to demonstrate the creation of functional components.