Making js conditional statements shorter

I’ve been messing around with a wp plugin that is missing some classes and stuff, and I figured I could add them myself through a custom script.
As you can see from the code I just selected a bunch of elements and I gave each one a unique classname that will later be used to add some css pseudo elements, but the best thing I could come up with is this long a55 statement lol
If some of you know a better way, your help will be greatly appreciated!

This is an html snippet of my area of interest:

<div class="side_by_side">
  <label for="fieldname6_1_rb7">
    <input
      aria-label="Van"
      name="fieldname6_1"
      id="fieldname6_1_rb7"
      class="field group required"
      value="489"
      vt="Van"
      type="radio"
    />
    <span>Van</span></label>
</div>

This is what my js looks like, which works as it is, but I’d like to know if there’s a better way to write something like this..

const modelInputLabel = document.querySelectorAll(".side_by_side span");
for (let i = 0; i < modelInputLabel.length; i++) {
  if (i === 0) {
    modelInputLabel[i].setAttribute("class", "test modelFirst");
  } else if (i === 1) {
    modelInputLabel[i].setAttribute("class", "test modelSecond");
  } else if (i === 2) {
    modelInputLabel[i].setAttribute("class", "test modelThird");
  } else if (i === 3) {
    modelInputLabel[i].setAttribute("class", "test modelFourth");
  } else if (i === 4) {
    modelInputLabel[i].setAttribute("class", "test modelFifth");
  } else if (i === 5) {
    modelInputLabel[i].setAttribute("class", "test modelSixth");
  } else if (i === 6) {
    modelInputLabel[i].setAttribute("class", "test modelSeventh");
  } else if (i === 7) {
    modelInputLabel[i].setAttribute("class", "test modelEight");
  }
}

>Solution :

Using forEach and index

const classNames = ["test modelFirst",
"test modelSecond",
"test modelThird",
"test modelFourth",
"test modelFifth",
"test modelSixth",
"test modelSeventh",
"test modelEight"];

const modelInputLabel = document.querySelectorAll(".side_by_side span");

modelInputLabel.forEach((modelInput, index) => {
    modelInput.setAttribute("class", classNames[index]);
});