1.Question:What's a difference between a DOM object and a virtual DOM object?
Answer:A virtual DOM object can update much faster than a regular DOM object.
A virtual DOM object can't directly affect HTML.
A virtual DOM object will be updated if ANY JSX element renders.
2.Question:What is the correct way to attach the function 'yo' to a click event?
let yo = () => {
alert('Yo');
};Answer:
<button onClick={yo}></button>3.Question:What's wrong with this code?
let skateboardDog = (
<img src="alfie.jpg" />
<h1>Hiya kids! I'm a dog on a skateboard.</h1>
);Answer:JSX expressions need an outermost element.
4.Question:What should you pass to ReactDOM.render() for its second argument?
Answer:A selector that matches an HTML element.
5.Question:What problem does the virtual DOM attempt to solve?
Answer:Updating DOM objects happens unnecessarily often.
6.Question:Which will render "100" to the screen?
Answer:
ReactDom.render(
<h1>{10 * 10}</h1>,
document.getElementById('app')
);7.Question:What should you pass to ReactDOM.render() for its first argument?
Answer:A JSX expression that you want to render.
8.Question:Place the following steps in the right order:
a. The screen looks different than it used to.
b. A JSX element renders.
c. The virtual DOM "diffs," comparing its current self with its previous self.
d. The entire virtual DOM updates.
e. Part of the real DOM updates.
Answer:b, d, c, e, a
9.Question:Can a web browser read JSX directly?
Answer:No, JSX must be compiled before it can be read by a web browser.