This HTML/CSS, JavaScript, and React Online Test Separates Good From Bad Hires

Every user on your website has an image avatar that is displayed when they post a comment. You want to style these images differently from other images on your site. Add a CSS class named avatar that fulfils the following requirements:

1. The avatar's border is rounded, so that it appears as a circle.
2. The avatar's width and height are both 150px.
3. The avatar has a solid border, has a width of 2px, and be colored gray.

For example, the avatar in the template should look like:

Implement the ensure function so that it throws an error if called without arguments or the argument is undefined. Otherwise it should return the given value.

Finish the FocusableInput component so that the input element automatically receives focus on the first render if the shouldFocus prop is true.

The component should use React Hooks.

A Mathematics tutoring web application for kids has a button that highlights all even numbers (in span), using 'yellow' as the background color. Clicking the button again removes the background. All further clicks add or remove the 'yellow' background alternately.

Currently, the button doesn't work as expected. For the given HTML markup and JavaScript function, select all options that will identify and fix the bugs in the JavaScript function:

<div id='numbers'>
 <span>1</span><span>2</span><span>3</span><span>4</span><span>5</span>
 <button id='btn' onclick='toggleEvenColor()'>Toggle even number highlighting</button>
</div>

1: function toggleEvenColor() {
2:   let spanElements = document.querySelectorAll('#numbers span');
3:   spanElements.forEach(function() {
4:     item.style.backgroundColor = 'transparent';
5:   });
6: }

Implement the removeProperty function which takes an object and property name, and does the following:

If the object obj has a property prop, the function removes the property from the object and returns true; in all other cases it returns false.

Update the website's HTML, without using JavaScript or CSS, to make use of semantic elements so that:

• The classless outer div element is replaced with a more appropriate element.
• The divs with the image and caption classes are replaced with self-contained content elements.
• The divs with the lorem-ipsum and description classes are replaced with elements, so that by default only the contents of the description element are shown. When the contents of the description element are clicked, the visibility of the rest of the lorem-ipsum element is toggled.

You've been sent a snippet from a spreadsheet, and have been asked to re-create it for display on the company's internal website.

Re-create the following spreadsheet using HTML, in a table appropriately captioned "Purchase Orders".

Write CSS so that the link <a href="http://www.testdome.com">Check documentation</a> looks like the one in the image below, and the cursor looks like a question mark when hovering over the link:

Write a function that converts user entered date formatted as M/D/YYYY to a format required by an API (YYYYMMDD). The parameter "userDate" and the return value are strings.

For example, it should convert user entered date "12/31/2014" to "20141231" suitable for the API.

An image gallery is a set of images with corresponding remove buttons. This is the HTML code for a gallery with two images:

<div class="image">
  <img src="https://bit.ly/3lmYVna" alt="First">
  <button class="remove">X</button>
</div>
<div class="image">
  <img src="https://bit.ly/3flyaMj" alt="Second">
  <button class="remove">X</button>
</div>

Implement the setup function that registers a click event handler and implements the following logic: When the button of class remove is clicked, its parent <div> element should be removed from the gallery.

For example, after the first image has been removed from the gallery above, it's HTML code should look like this:

<div class="image">
  <img src="https://bit.ly/3flyaMj" alt="Second">
  <button class="remove">X</button>
</div>

Fix the bugs in the following HTML code.

The Message component contains an anchor element and a paragraph below the anchor. Rendering of the paragraph should be toggled by clicking on the anchor element using the following logic:

• At the start, the paragraph should not be rendered.
• After a click, the paragraph should be rendered.
• After another click, the paragraph should not be rendered.

Finish the Message component by implementing this logic.

Your company assigns each customer a membership ID, and you are implementing a check digit for those IDs.

The check digit should be calculated by adding up all digits in each membership ID. If the result of the sum is a number with more than a single digit, another iteration is required, and the digits of the result also should be added together. This process should repeat until a single-digit number is calculated.

For example, for the membership ID "55555" the sum of all digits is 25. Because this is not a single-digit number, 2 and 5 would be added, and the result, 7, would be the check digit.

The TextInput component renders an input element in the DOM and accepts a ref that is forwarded to that input element. Finish the FocusableInput component:

• The component should accept a focused prop.
• When the focused prop is changed from false to true, and the input is not focused, it should receive the focus.
• If on mounting the focused prop is true, the input should receive the focus.

A playlist is considered a repeating playlist if any of the songs contain a reference to a previous song in the playlist. Otherwise, the playlist will end with the last song which points to undefined.

Implement the method isRepeatingPlaylist that, efficiently with respect to time used, returns true if a playlist is repeating or false if it is not.

For example, the following code prints "true" as both songs point to each other.

let first = new Song("Hello");
let second = new Song("Eye of the tiger");

first.nextSong = second;
second.nextSong = first;

console.log(first.isRepeatingPlaylist());

Write a TodoList component that expects an items prop which is a list of objects, each with text and done properties.

TodoList also accepts an onItemClick function prop, which should be called when a user clicks an item in the list, if the item is not marked as done. Otherwise, the onItemClick should not be called and the click event itself should not be propagated further. The function should be called with the item object from the items list as the first parameter and the event as the second parameter.

Write the function newMessage, which receives the name of the topic as the parameter. Function should change the background color of the p tag to red where the data-topic-name is topicName. A topicName that doesn't have a matching data-topic-name should be ignored.

For example, if the HTML is:

<div>
  <p data-topic-name="discussion">General discussion</p>
  <p data-topic-name="bugs">Bugs</p>
  <p data-topic-name="animals">Animals</p>
</div>

After calling newMessage("discussion") the HTML should be:

<div>
  <p data-topic-name="discussion" style="background-color: red;">General discussion</p>
  <p data-topic-name="bugs">Bugs</p>
  <p data-topic-name="animals">Animals</p>
</div>

Write a function that, when passed an array and a target sum, returns, efficiently with respect to time used, two distinct zero-based indices of any two of the numbers, whose sum is equal to the target sum. If there are no two numbers, the function should return null.

For example, findTwoSum([ 3, 1, 5, 7, 5, 9 ], 10) should return an array containing any of the following pairs of indices:

• 0 and 3 (or 3 and 0) as 3 + 7 = 10
• 1 and 5 (or 5 and 1) as 1 + 9 = 10
• 2 and 4 (or 4 and 2) as 5 + 5 = 10

Consider the following React components:

const SecurityContext = React.createContext({ username: "", permissions: [] });

const ControlsComponent = (props) => {
  return (
    <SecurityContext.Provider value={{ username: props.username }}>
      <LogoutWrapper></LogoutWrapper>
    </SecurityContext.Provider>
  );
};

const LogoutWrapper = (props) => {
  var context = React.useContext(SecurityContext);
  
  return (
    <div>
      <p>{context.username}</p>
      <button>Click here to logout</button>
    </div>
  );
};

Select all the correct statements if ControlsComponent is rendered with the username prop equal to "James".

You're making the 'Buy' button for a movie ticket website, which has the class buy-button.

The buy-button class has the following CSS:

.buy-button {
  width: 100px;
  height: 100px;
  background: Orange;
  /* Make it a circle */
  border-radius: 50%;
  /* Center horizontally and vertically */
  display: flex;
  justify-content: center;
  align-items: center;
}

A 1 second animation named wiggle should be added to it so the button wiggles when the mouse hovers over it.

Rotating to 25 degrees clockwise (first 0.33 s), then to 25 degrees counterclockwise (second 0.33 s) and then returning to the original position.

It should look like this:

Which of the following would produce the desired animation?

With the new HTML5 features, modify the form so that:

• The formula input field suggests the following options when the user starts to type: "sin", "cos", "tan" and "cot".
• The iterations input field is a slider with possible values from 1 to 10.
• The precision input field is a number picker with possible values from 1 to 100, where 50 is the default value.

An HTML div element contains lists of endangered species grouped by continent and the species population status.

<div>
    <ul data-continent="North America">
        <li data-species="California condor">Critically Endangered</li>
        <li data-species="American bison">Near Threatened</li>
    </ul>
    <ul data-continent="Europe">
        <li data-species="Cave bear">Extinct</li>
    </ul>
</div>

Implement the function endangeredSpecies that returns how endangered a species is on a particular continent.

For example, endangeredSpecies('North America', 'American bison') should return 'Near Threatened'.

As part of a data processing pipeline, complete the implementation of the pipeline function:

• The pipeline function should accept a variable number of functions, and it should return a new function that accepts one parameter arg.
• The returned function should call the first function in the pipeline with the parameter arg, and call the second function with the result of the first function.
• The returned function should continue calling each function in the pipeline in order, following the same pattern, and return the value from the last function.

For example, pipeline(x => x * 3, x => x + 1, x => x / 2) then calling the returned function with 3 should return 5.0.

This application should allow the user to update their username by inputting a custom value and clicking the button.

The Username component is finished and should not be changed, but the App component is missing parts. Finish the App component so that the Username component displays the inputted text when the button is clicked.

The App component should use the React.useRef Hook to pass the input to the Username component for the input element and for the Username component.

For example, if the user inputs a new username of "John Doe" and clicks the button, the div element with id root should look like this:

<div><button>Change Username</button><input type="text"><h1>John Doe</h1></div>

Fix the bugs in the registerHandlers function. An alert should display anchor's zero-based index within a document instead of following the link.

For example, in the document below, the alert should display "2" when Google anchor is clicked since it is the third anchor element in the document and its zero-based index is 2.

<body>
  In my life, I used the following web search engines:<br/>
  <a href="//www.yahoo.com">Yahoo!</a><br/>
  <a href="//www.altavista.com">AltaVista</a><br/>
  <a href="//www.google.com">Google</a><br/>
</body>

Function appendChildren should add a new child div to each existing div. New divs should be decorated by calling decorateDiv.

For example, after appendChildren is executed, the following divs:

<div id="a">
  <div id="b">
  </div>
</div>

should take the following form (assuming decorateDiv does nothing):

<div id="a">
  <div id="b">
    <div></div>
  </div>
  <div></div>
</div>

The code below should do the job, but for some reason it goes into an infinite loop. Fix the bugs.

Using CSS only (without adding additional HTML attributes), style articles so that they occupy the whole browser window and have the following properties:

A website needs a list where users can rank their favorite foods. Write the setup function, which should register click handlers on all Up! and Down! buttons. The Up! button should move the list item one place up in the list, while Down! button should move the list item one place down in the list.

For example, consider this code:

document.body.innerHTML = `<ol>
  <li><button>Up!</button>Taco<button>Down!</button></li>
  <li><button>Up!</button>Pizza<button>Down!</button></li>
  <li><button>Up!</button>Eggs<button>Down!</button></li>
</ol>`;

setup();

If the button Up! button in Pizza list item is clicked, Pizza should be the first item in the list, while Taco should be the second item.

You have a GroceryApp component, which receives a list of products, each one with name and votes. The app should render an unordered list, with a list item for each product. Products can be upvoted or downvoted.

By appropriately using React state and props, implement the upvote/downvote logic. Keep the state in the topmost component, while the Product component should accept props.

For example, passing the following array as products prop to GroceryApp [{ name: "Oranges", votes: 0 }, { name: "Bananas", votes: 0 }] and clicking the '+' button next to the Oranges should result in HTML like:

<div id="root">
  <ul>
    <li>
      <span>Oranges</span> - <span>votes: 1</span><button>+</button> <button>-</button>
    </li>
    <li>
      <span>Bananas</span> - <span>votes: 0</span><button>+</button> <button>-</button>
    </li>
  </ul>
</div>

The following HTML represents a family tree:

<James>
  <Dave></Dave>
  <Mike></Mike>
  <Sarah></Sarah>
</James>

Implement the closestRelative function so that when a parent HTML element is passed, the function returns the parent's closest relative whose name matches the relativeName, and obeys the following rules:

• The parent parameter is the HTML element of which the closest relative will be a descendant.
• Each member of the family, including children, may also be a parent to one or more children.
• Children are more closely related to the parent than grandchildren.
• If several children in the same generation have the same name, then the first child in the tree is considered the closer relative.
• If no matching relative is found the function should return null.

For example, the below code should print 'MIKE' for the given family tree:

let parent = document.getElementsByTagName('James')[0];
let relative = closestRelative(parent, 'Mike');
console.log(relative && relative.tagName); // prints MIKE

Implement the showCustomers function so that it renders customers as list items. The first argument to the function, customers, is an array of objects with the name and email properties. The second argument to the function, targetList, is an unordered HTML list to which each customer should be added as a separate list item.

The name and email properties should be added as two paragraphs inside the list item. At first, the email paragraph element should not be present in the DOM. The email paragraph element should be added to the DOM after the name is clicked, and it should be removed from the DOM when the name is clicked again.

For example, the following code:

document.body.innerHTML = `
<div>
  <ul id="customers">
  </ul>
</div>
`;
let customers = [{name: "John", email: "john@example.com"},
                 {name: "Mary", email: "mary@example.com"}];
showCustomers(customers, document.getElementById("customers"));

let customerParagraph = document.querySelectorAll("li > p")[0];
if(customerParagraph) {
  customerParagraph.click();
}
console.log(document.body.innerHTML);

Should render:

<div>
  <ul id="customers">
    <li>
      <p>John</p>
      <p>john@example.com</p>
    </li>
    <li>
      <p>Mary</p>
    </li>
  </ul>
</div>

An image gallery is a set of images with corresponding remove buttons. This is the HTML code for a gallery with two images:

<div>
  <div class="image">
    <img src="https://bit.ly/3lmYVna">
    <button class="remove">X</button>
  </div>
  <div class="image">
    <img src="https://bit.ly/3flyaMj">
    <button class="remove">X</button>
  </div>
</div>

Implement the ImageGallery component that accepts a links prop and renders the gallery described above so that the first item in the links prop is the src attribute of the first image in the gallery. It should also implement the following logic: When the button is clicked, the image that is in the same div as the button should be removed from the gallery.

For example, after the first image has been removed from the gallery above, it's HTML code should look like this:

<div>
  <div class="image">
    <img src="https://bit.ly/3flyaMj">
    <button class="remove">X</button>
  </div>
</div>