Animation delay between elements

Issue

I have a simple reveal animation created with javascript, the problem im having is that the elements on the same row all enter together and i will like to have a small delay between them that im not beeing able to achieve. On mobile as they stack its ok the problem is with desktop. Hope someone can help me. Many thanks

function reveal() {
  var reveals = document.querySelectorAll(".reveal");

  for (var i = 0; i < reveals.length; i++) {
    var windowHeight = window.innerHeight;
    var elementTop = reveals[i].getBoundingClientRect().top;
    var elementVisible = 150;

    if (elementTop < windowHeight - elementVisible) {
      reveals[i].classList.add("active");
    } else {
      reveals[i].classList.remove("active");
    }
  }
}

window.addEventListener("scroll", reveal);

*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Arial", sans-serif;
}
body{
  background: #42455a;
}
section{
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}
section:nth-child(1){
  color: #e0ffff;
  }
section:nth-child(2){
  color: #42455a;
  background: #e0ffff;
} 
section:nth-child(3){
  color: #e0ffff;
}
section:nth-child(4){
  color: #42455a;
  background: #e0ffff;
}
section .container{
  margin: 100px;
}
section h1{
  font-size: 3rem;
  margin: 20px;
}
section h2{
  font-size: 40px;
  text-align: center;
  text-transform: uppercase;
}
section .text-container{
   display: flex;
}
section .text-container .text-box{
  margin: 20px;
  padding: 20px;
  background: #00c2cb;
}
section .text-container .text-box h3{
  font-size: 30px;
  text-align: center;
  text-transform: uppercase;
  margin-bottom: 10px;
}

@media (max-width: 900px){
  section h1{
    font-size: 2rem;
    text-align: center;
  }
  section .text-container{
    flex-direction: column;
  }
}

.reveal{
  position: relative;
  transform: translateY(150px);
  opacity: 0;
  transition: 1s all ease;
}

.reveal.active{
  transform: translateY(0);
  opacity: 1;
}

<section>
  <h1>Scroll Down to Reveal Elements &#8595;</h1>
</section>
<section>
  <div class="container">
    <h2>Caption</h2>
    <div class="text-container">
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
    </div>
  </div>
</section>

<section>
  <div class="container">
    <h2>Caption</h2>
    <div class="text-container">
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
    </div>
  </div>
</section>

<section>
  <div class="container">
    <h2>Caption</h2>
    <div class="text-container">
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore
          eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
    </div>
  </div>
</section>

Solution

You could use a timeout to delay them according to their index insed their respective .container.

Something like

function reveal() {
  const windowHeight = window.innerHeight;
  const elementVisible = 150;
  const visibilityLimit = windowHeight - elementVisible;
  const containers = document.querySelectorAll(".container");

  containers.forEach(container => {
    const reveals = container.querySelectorAll(".reveal");
    reveals.forEach((reveal, index) => {
      const elementTop = reveal.getBoundingClientRect().top;
      if (elementTop < visibilityLimit) {
        setTimeout(() => {
          reveal.classList.add("active")
        }, index * 250);
      } else {
        reveal.classList.remove("active");
      }
    });
  });
}

window.addEventListener("scroll", reveal);

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Arial", sans-serif;
}

body {
  background: #42455a;
}

section {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

section:nth-child(1) {
  color: #e0ffff;
}

section:nth-child(2) {
  color: #42455a;
  background: #e0ffff;
}

section:nth-child(3) {
  color: #e0ffff;
}

section:nth-child(4) {
  color: #42455a;
  background: #e0ffff;
}

section .container {
  margin: 100px;
}

section h1 {
  font-size: 3rem;
  margin: 20px;
}

section h2 {
  font-size: 40px;
  text-align: center;
  text-transform: uppercase;
}

section .text-container {
  display: flex;
}

section .text-container .text-box {
  margin: 20px;
  padding: 20px;
  background: #00c2cb;
}

section .text-container .text-box h3 {
  font-size: 30px;
  text-align: center;
  text-transform: uppercase;
  margin-bottom: 10px;
}

@media (max-width: 900px) {
  section h1 {
    font-size: 2rem;
    text-align: center;
  }
  section .text-container {
    flex-direction: column;
  }
}

.reveal {
  position: relative;
  transform: translateY(150px);
  opacity: 0;
  transition: 1s all ease;
}

.reveal.active {
  transform: translateY(0);
  opacity: 1;
}

<section>
  <h1>Scroll Down to Reveal Elements &#8595;</h1>
</section>
<section>
  <div class="container">
    <h2>Caption</h2>
    <div class="text-container">
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
    </div>
  </div>
</section>

<section>
  <div class="container">
    <h2>Caption</h2>
    <div class="text-container">
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
    </div>
  </div>
</section>

<section>
  <div class="container">
    <h2>Caption</h2>
    <div class="text-container">
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
      <div class="text-box reveal">
        <h3>Section Text</h3>
        <p>
          Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempore eius molestiae perferendis eos provident vitae iste.
        </p>
      </div>
    </div>
  </div>
</section>

Answered By - Gabriele Petrioli