ReactJs: Lifecycle & State
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Total 20 question (100 marks)
1. props in react can________.
2. What is the smallest building block of ReactJS?
3. What happens when the following render() method executes? render(){ let langs = ["Ruby","ES6","Scala"] return (<div>
4. What is the default local host port that a React development server uses?
5. At the highest level, React components have lifecycle events that fall into.
6. React keeps track of what items have changed, been added, or been removed from a list using ________.
7. React can only render elements in the root document element.
8. What type of element will be rendered from the following code? function Hello() { return <h1>Hello reactjs</h1>; } ReactDOM.render(<Hello />, document.getElementById('root'));
9. JSX is faster because it performs ____________ while compiling code to JavaScript
10. When rendering a list using the JavaScript map() method, what is required for each element rendered?
11. How can you optimze performance for a function component that always renders the same way?
12. What is the children prop?
13. To develop and run React code, Node.js is required.
14. How can we prevent default behavior in React? What method you can call?
15. What command is used to start the React local development server?
16. What tool does React use to compile JSX?
17. In JSX most of the errors can be caught during _________.
18. Invoked once, only on the client, after rendering occurs.
19. If you want to import just the Component from the React library, what syntax do you use?
20. React separates the user interface into components. How are components combined to create a user interface?
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