React.js Part-IV

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React.js Part-IV

In this component, how do you display whether the user was logged in or not? *

1 point

The user is loggedIn ? logged in : not logged in.

Write a function to check the login status.

The user is {isLoggedIn = "no"}.

The user is {isLoggedIn ? "logged in." : "not logged in"}.

The code below is rendering nothing, and there is an error that says "ReactDOM is not defined." How do you fix this issue? *

1 point

render(element, document.getElementById("root"));

ReactDOM(element, document.getElementById("root"));

renderDOM(element, document.getElementById("root"));

DOM(element, document.getElementById("root"));

Other:

You are rendering a list with React when this warning appears in the console: "Warning: Each child in a list should have a unique 'key' prop." How do you fix this issue? *

1 point

Pass the name of each item as its key.

Add a key prop with the same value to each item the list.

Clear the console warnings.

When iterating over the list items, add a unique property to each list item.

What is the process of deciding whether an update is necessary? *

1 point

shadow DOM

fiber

reconciliation

setting state

Given this code, what will be printed in the <h1> tag? *

1 point

It will produce an error saying "cannot read property "length" of undefined."

undefined

What is wrong with this code? *

1 point

React components cannot be defined using functions.

React does not allow components to return more than one element.

The component needs to use the return keyword.

String literals must be surrounded by quotes.

Add the code that will fire the photon torpedoes when the button is clicked. *

1 point

How might you check property types without using Flow or TypeScript? *

1 point

Check Manually.

Use prop-helper.

use prop-types.

user checker-types.

Describe what is happening in this code? *

1 point

It is creating a new object that contains the same name property as the person object.

It is assigning the value of the person object's firstName property to a constant called name.

It is retrieving the value of person.name.firstName.

It is assigning the value of the person object's name property to a constant called firstName.

React is an open-source project but is maintained by which company? *

1 point

Intuit

Twitter

Facebook

Snapchat

How do you add an id of heading to the following h1 element? *

1 point

let dish = <h1 id={heading}>Mac and Cheese</h1>;

let dish = <h1 id="heading">Mac and Cheese</h1>;

let dish = <h1 id:"heading">Mac and Cheese</h1>;

let dish = <h1 class="heading">Mac and Cheese</h1>;

Which tool is not part of Create React App? *

1 point

React

jQuery

webpack

ReactDOM

What is the JavaScript syntax extension that is commonly used to create React elements? *

1 point

HTML

JavaScriptX

JSX

React JavaScript

What is the browser extension called that React developers use to debug applications? *

1 point

React Developer Tools

React Tooling Add-on

React Codewatch

React Debug

How would you generate the boilerplate code for a new app that you are building to collect underpants? *

1 point

npm create-react-app collect-underpants

npx start-app collect-underpants

react new collect-underpants

npx create-react-app collect-underpants

When using a portal, what is the second argument? *

1 point

the App component

the page

the current state

the DOM element that exists outside of the parent component

What is the first file loaded by the browser in a basic React project? *

1 point

src/App.js

src/index.js

public/manifest.json

public/index.html

What is this pattern called? *

1 point

object destructuring

array destructuring

spread operating

code pushing

What command can you use to generate a React project? *

1 point

react-starter

create-react-app

react-gen

react-start

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