Определение количества выводимых строк в зависимости от длины текста

const articles = document.querySelectorAll('.article');

articles.forEach(article => {
  const header = article.querySelector('.header');
  const content = article.querySelector('.content');

  const headerStyle = window.getComputedStyle(header, null);

  const headerBoxSizing = headerStyle.getPropertyValue('box-sizing');
  const headerFontSize = parseInt(headerStyle.getPropertyValue('font-size'));

  let headerLineHeader = parseInt(headerStyle.getPropertyValue('line-height'));
  let headerHeight = parseInt(headerStyle.getPropertyValue('height'));

  if (isNaN(headerLineHeader)) {
    // Значения по умолчанию для line-height это 1.2
    headerLineHeader = headerFontSize * 1.2;
  }

  if (headerBoxSizing === 'border-box') {
    const paddingTop = parseInt(headerStyle.getPropertyValue('padding-top'));
    const paddingBottom = parseInt(headerStyle.getPropertyValue('padding-bottom'));
    const borderTop = parseInt(headerStyle.getPropertyValue('border-top-width'));
    const borderBottom = parseInt(headerStyle.getPropertyValue('border-bottom-width'));

    headerHeight = headerHeight - paddingTop - paddingBottom - borderTop - borderBottom;
  }

  const lines = Math.ceil(headerHeight / headerLineHeader);

  switch (lines) {
    case 4:
      content.style.setProperty('--line-clamp', 12);
      break;

    case 3:
      content.style.setProperty('--line-clamp', 8);
      break;

    case 2:
      content.style.setProperty('--line-clamp', 4);
      break;
  }
});

*,
*:after,
*:before {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  width: 100%;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.container {
  display: grid;
  gap: 36px;
  grid-template-columns: repeat(1, minmax(0, 1fr));
}

.article {
  box-shadow: 0 0 4px 2px rgba(0, 0, 0, .1);
  padding: 6px 12px;
}

.article .content {
  --line-clamp: 3;
  display: -webkit-box;
  -webkit-line-clamp: var(--line-clamp);
  -webkit-box-orient: vertical;
  overflow: hidden
}

@media (min-width: 768px) {
  .container {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  .container {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 1536px) {
  .container {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

<div class="container">
  <div class="article">
    <h1 class="header">1<br />2<br />3<br />4<br /></h1>
    <p class="content">On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and
      equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is
      untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently
      occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse
      pains.
    </p>
  </div>

  <div class="article">
    <h1 class="header">1<br />2<br />3</h1>
    <p class="content">On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and
      equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is
      untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently
      occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse
      pains.
    </p>
  </div>

  <div class="article">
    <h1 class="header">1<br />2</h1>
    <p class="content">On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and
      equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is
      untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently
      occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse
      pains.
    </p>
  </div>
</div>