React (37)

Fill the blank to display a property keywords:

class Search extends React.Component {
    
    constructor() {
        super();
        this.state = {
            keywords: "JavaScript"
        };
    }

    render() {
        return  (
            <p>{.keywords}</p>
        );
    }
}
ReactDOM.render(<Search/>, document.body);

 The component's state:

 contains data props that were defined by the caller of this component

 contains data specific to this component that may change over time

 provide a way to access DOM nodes or React elements created in the render method

 let you group a list of children without adding extra nodes to the DOM

Is it possible to split JSX over multiple lines in React?

const element = <h1>Hello,
        Kate
        Simson
        !</h1>;

ReactDOM.render(element, document.getElementById('root'));

 yes

 no

JSX doesn't allow to use self-closing tags. True or false?

<UserProfile />

 true

 false

What shows in console when a user clicks the button?

class MyButton extends React.Component {
    state = {
        x: 1,
        y: 2
    };

    render() {
        return  (
            <button onClick={this.handleClick}>click me</button>
        );
    }
    handleClick = () => {
        this.setState({
            x: 10,
            y: 20
        }, () => {
            console.log(this.state);
        });
    }
}
ReactDOM.render(<MyButton/>, document.getElementById("root"));

 {x: 1, y: 2}

 {x: 10, y: 20}

 nothing

 throw an error

Which of the following examples are the proper ways to update the local state in the class component in React?

this.setState("keywords", value)

 this.setState({keywords: value})

 this.setState(["keywords", value])

 this.setState((state) => ({keywords: value}))

Which of the following method should be used to initialize local state when you use createReactClass function?

 initState

 getInitialState

 setInitialState

 bootState

In React local state can be used by:

 function component

 class component

 both class and function component

Which of the following method is used to update state in React?

 updateState

 setState

 initState

 refreshState

setState() is:

 always synchronous

 always asynchronous

 sometimes synchronous

 sometimes asynchronous