does props go from parent to child or from child to parent in react js

Question

I am having a confusion, we say react js has unidirectional flow which means props can be sent from parent to child only. But then why do we write super(props);??

generally we write

class Test extends React.Component { 
    constructor(props) 
    { 
        super(props); 
        this.state = { hello : "World!" }; 
    }
}

so why are we sending props from child to parent?? I expect explanation to my question

[**`super`**](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/super) has nothing to do with react, but rather object inheritance in javascript. React uses class syntax, your subclasses are extending from `React.Component`. That is a parent react class that sets up its lifecycle so you have methods like `componentDidMount`. This is unrelated to props that one component sends to another — John Ruddell, Jul 15 '19 at 17:01
Yes, you want to call the parent class constructor so the components lifecycle and other operations are setup. Read the docs on super, i posted a link — John Ruddell, Jul 15 '19 at 17:04
Possible duplicate of [What does calling super() in a React constructor do?](https://stackoverflow.com/questions/40433463/what-does-calling-super-in-a-react-constructor-do) — John Ruddell, Jul 15 '19 at 17:08

score 1 · Answer 1 · answered Jul 15 '19 at 17:02

But then why do we write super(props);

That has nothing to do with the parent/child relationship of components. That has to do with the superclass/subclass relationship between React.Component and class Test extends React.Component. super(props) calls the React.Component constructor, passing in the props.

does props go from parent to child or from child to parent in react js

1 Answers1