React (39)

Fill the blank to display the current state value:

import { useState } from 'react';

function Search() {
  const state = useState("JavaScript");

  return <p>{}</p>;
}​​​​​​​

 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?

​​​​​​​​import { createRoot } from "react-dom/client";
const element = (<h1>Hello,
                    Kate        
                    Simson        
                    !</h1>);
​​​​​​​
const root = createRoot(document.getElementById("root"));
root.render(element);​​​​​

 yes

 no

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

<UserProfile />

 true

 false

What shows in the paragraph when a user clicks the button?

function MyButton({ x = 10 }) {

  function handleClick() {
    x = 20;
  }
​​​​​​​
  return (
    <div>
      <p>{x}</p>
      <button onClick={handleClick}>click me</button>
    </div>
​​​​​​​  );
}​​​​​​​

 10

 20

 nothing

 throw an error

In React props is:

 immutable

 mutable

What shows in the paragraph when a user clicks the button?

import { useState } from 'react';

function MyButton() {
  const [state, setState] = useState({
    x: 1,
    y: 2
  });

  const handleClick = () => {
    setState({
      x: 10,
      y: 20
    });
  };

  return (
    <div>
      <p>{state.x}, {state.y}</p>
      <button onClick={handleClick}>click me</button>
    </div>
  );
}

 1, 2

 10, 20

 1, 20

 undefined

Which of the following are proper ways to update local state in a function component in React?

const [state, setState] = useState({
  keywords: ""
});

 setState("keywords", value)

​​​​​​​​​​​​​​ setState(prevState => ({ ...prevState, keywords: value }))

​​​​​​​ state.keywords = value

​​​​​​​ setState({keywords: value})​​​​​​​​​​​​​​​

How can local state be initialized in a function component?

 initState

 useState

 createState

 bootState

Which Hook can be used to add local state to a function component?

 useState

 useEffect

 createState

 useRef​​​​​​​