stack3 with paste

by Julian

HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Word Index Tracker</title>
   
</head>
<body>

<form id="indexer">
  <button id="toggle" class="off" type="button"></button>
  <fieldset id="source">
    Paste text here
  </fieldset>
  <output id="selected">
    <ol></ol>
  </output>
</form>
 </body>
</html>

CSS

:root {
  font: 2ch/1.5 "Segoe UI"
}

#toggle {
  margin-bottom: 1rem;
  padding: 5px 10px;
  border-radius: 8px;
  font: inherit;
  cursor: pointer;
  background: 
  radial-gradient(
    ellipse at center,    
    rgba(197,222,234,1) 0%,
    rgba(138,187,215,1) 31%,
    rgba(6,109,171,1) 100%);
}

#toggle::before {
  content: "Edit Mode"
}

#toggle::after {
  content: " ON";
}

#toggle.off {
  color: #fff;
  background: 
  radial-gradient(
    ellipse at center,
    rgba(125, 126, 125, 1) 0%, 
    rgba(14, 14, 14, 1) 100%);
}

JavaScript

// Reference <form>
const form = document.forms.indexer;
/**
 * Reference all form controls of <form>
 * In this layout it is:
 *   - <button>
 *   - <fieldset>
 *   - <output>
 */
const io = form.elements;
// Reference <button>
const btn = io.toggle;
// Reference <fieldset>
const src = io.source;
// Reference <output>
const sel = io.selected;
// Declaration for two arrays (not made yet).
let marked;
let indices;

/**
 * Index each word by extracting the string,
 * converting the string into an array of 
 * substrings, and wrapping each word with
 * a <mark> element. Each <mark> is then 
 * assigned a [data-idx] attribute with the 
 * corresponding index number.
 */
const indexText = () => {
  const text = src.innerText;
  let marks = text.split(" ");
  marks[0] = `<mark>${marks[0]}`;
  marks[marks.length - 1] = `${marks[marks.length - 1]}</mark>`;
  src.innerHTML = marks.join(`</mark> <mark>`).trim();
  marked = [...document.querySelectorAll("mark")];
  marked.forEach((mrk, idx) => mrk.dataset.idx = idx);
};

/**
 * Handle "click" event when the user clicks
 * button#toggle. Basically an on/off switch
 * for whether fieldset#source can be edited
 * and when the text can be indexed.
 * @param {object} e - Event object
 */
const editText = (e) => {
  e.target.classList.toggle("off");
  src.toggleAttribute("contenteditable");
  indexText();
};

/**
 * Handle "click" event when user clicks
 * a word. Each word is inside a <mark> and
 * it's background color will change, and
 * it's text and index number will be listed
 * in output#selected > ol.
 * @param {object} e - Event object
 */
const highLight = (e) => {
  const clk = e.target;
  if (clk.matches("mark")) {
    clk.classList.toggle("highlight");
  }
  indices = [...document.querySelectorAll(".highlight")]
    .map(h => {
      let txt = h.innerText;
      txt = txt.replace(/[^A-Z0-9]$/i, "");
      return `
    <li>${txt}
    ${h.dataset.idx}</li>
    `;
    });
  sel.firstElementChild.innerHTML =...