How change state or property of an outer / separate component in reactjs?

Question

Current DOM tree is like:

<comp1>
  <div>
      <comp2></comp2>
      <comp3>
         <comp4 />
         <comp4 />
         .........
         .........
         .........
      </comp3>
  </div>
  <comp5></comp5>  
</comp1>

Component5 ie is my modal. I want to set it's state and props by onclick event on

My objective is to display the detail data on a modal based on the selection. So I need to set the state and props of modal component accordingly. How can I that in the current structure?

Answer 1

The old fashioned way, which is fine for a small page, is to move all states into the root node ( comp1 ). Other components become stateless. The root node passes to its children the properties they want to render, alongside the setters required to mutate the properties. For instance, comp5 gets a property username which is just the value of comp1.state.username , plus a property setUsername , which is a function taking a username string parameter in which comp1 uses setState to update its state's username . This way comp5 can render and update the username, and other components are aware of the change ( setState triggers a render of children).

For more complex apps, passing all these properties to children gets tedious, and you can resort to framework like flux and redux .

Answer 2

i think standard way of doing it is something like this

in your react component:

constructor(props) {
    ...
    this.state = {selectedComp4:  null
        ...
        }
    }
...
handleSelectedComp4Change (yourData) {
    this.setState({selectedComp4: yourData})
}
...
render() {
...
    return (
    <comp1>
    <div>
        <comp2></comp2>
        <comp3>
            <comp4 onSelectedComp4Change = {this.handleSelectedComp4Change}/>
            <comp4 onSelectedComp4Change = {this.handleSelectedComp4Change}/>
             ...
        </comp3>
    </div>
    <comp5 SelectedComp4={this.state.selectedComp4}></comp5>  
    </comp1>
    )
}

in comp4 send your data: onClick={() => { this.props.onSelectedComp4Change(someData) }}

in comp5 use your data in this.props.SelectedComp4

EDIT:

just like @Valéry said