How to convert a JavaScript function into a jQuery one?

Question

I have this JavaScript function and I want to have the same but in jQuery but it's not working correctly, the list items are not appearing:

function showList(section, books) {
  let olBooks = document.createElement("ol");
  let liBook = null;

  for (let book of books) {
    liBook = document.createElement("li");
    liBook.id = value.id;
    liBook.classList.add(CLASS_BOOK);
    liBook.innerHTML = "<p>" + booksInHTML(book) + "</p>";
    olBooks.appendChild(liBook);
  }
  section.append(olBooks);
}

With jQuery is not working:

function showList(section, books) {
   var olBooks = $("<ol/>");

    $.each( books, function( index, value ) {
     var liBook =  $("<li/>");

     liBook.id = value.id;
     liBook.classList.add(CLASS_BOOK);
     liBook.text("<p>" + bookInHTML(value) + "</p>");
    olBooks.append(liBook);
  });
  section.append(olBooks);
}

CertainPerformance · Accepted Answer · 2020-05-24 19:00:56Z

4

To set the id property with jQuery, you need to use .prop (or, less desirably, .attr):

liBook.prop('id', value.id);

Also, to set the class of an element with jQuery, use addClass:

liBook.addClass('CLASS_BOOK');

Also, to set the HTML of an element with jQuery, use the .html method. If you use the .text method, the result will set the text content of the element, not the HTML:

liBook.html("<p>" + bookInHTML(value) + "</p>");

But concatenating HTML strings from possibly untrustworthy user input can allow for arbitrary code execution, which is a security risk - it's also inelegant. Consider selecting the <p> first, and setting its .text:

$("<li><p></p></li>")
  .appendTo(liBook)
  .prop('id', value.id)
  .addClass(CLASS_BOOK)
  .find('p')
  .text(bookInHTML(value));

Live demo:

function showList(section, books) {
  var olBooks = $("<ol/>").appendTo(section);
  $.each(books, function(index, value) {
    $("<li><p></p></li>")
      .appendTo(olBooks)
      .prop('id', value.id)
      .addClass(CLASS_BOOK)
      .find('p')
      .text(bookInHTML(value));
  });
}

const CLASS_BOOK = '';
const bookInHTML = arg => arg;
showList(section, ['foo', 'bar']);

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="section"></div>

edited May 24, 2020 at 19:00

answered May 24, 2020 at 18:53

CertainPerformance

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5 Comments

Sebastian B. Over a year ago

As an explainer, $("<li/>") syntax doesn't create a regular DOM element, but rather a jQuery collection containing the new element, where you can operate on with jQuery API.

John Over a year ago

Thanks but like that the list items also don't appear.

Sebastian B. Over a year ago

This should also work: $("<li/>") .prop('id', value.id) .addClass(CLASS_BOOK) .append($("<p/>") .text(bookInHTML(value)) .appendTo(liBook);

Sebastian B. Over a year ago

@John maybe the DOM isn't there when your code is running. Is your code wrapped in a jQuery.ready()?

CertainPerformance Over a year ago

@John Works fine here, see snippet

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