Jack has created a React application that contains the CourseList component with state courses as shown below.const CourseList = () => { const [courses,setCourses] = useState([ ]) const [success, setSuccess] = useState('')}He wants to retrieve the list of courses available for registration from the database within the CourseList component. He wants the courses data to be rendered immediately when the component is rendered. Which of the following code snippet helps Jack to achieve the above requirement?useEffect(() => { // asynchronous call },[]);useEffect(() => { // asynchronous call },[courses]);useEffect(() => { // asynchronous call },[courses,success]);useEffect(() => { // asynchronous call },[success]);
Question
Jack has created a React application that contains the CourseList component with state courses as shown below.const CourseList = () => { const [courses,setCourses] = useState([ ]) const [success, setSuccess] = useState('')}He wants to retrieve the list of courses available for registration from the database within the CourseList component. He wants the courses data to be rendered immediately when the component is rendered. Which of the following code snippet helps Jack to achieve the above requirement?useEffect(() => { // asynchronous call },[]);useEffect(() => { // asynchronous call },[courses]);useEffect(() => { // asynchronous call },[courses,success]);useEffect(() => { // asynchronous call },[success]);
Solution
The correct code snippet for Jack to achieve his requirement would be:
useEffect(() => {
// asynchronous call
},[]);
This is because the useEffect hook with an empty dependency array [] will only run once, similar to componentDidMount() in a class component. This is perfect for fetching data when the component is first rendered.
The other options are not correct because they will cause the useEffect hook to run every time the courses or success state changes, which is not necessary in this case. Jack only needs to fetch the data once when the component is first rendered.
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