JSFiddle - React, Tailwind, and code Playground

HTML

<form class="email-form" action="" method="PUT" data-remote="true" data-method="put">

    <ul>
        <li><label for="sEmail1"><input type="text" id="sEmail1" name="emails[]" value="[email protected]" placeholder=""></label></li>
        <li><label for="sEmail2"><input type="text" id="sEmail2" name="emails[]" value="[email protected]" placeholder=""></label></li>
        <li><label for="sEmail3"><input type="text" id="sEmail3" name="emails[]" value="[email protected]" placeholder=""></label></li>
    </ul>


    <button type="submit">Continue</button>

</form>

JavaScript

parameters = new Object();
    parameters.emails = new Object()
    parameters.emails.list= [];
    i = 0;

    $("input[name^='email']").each(function(){
       if(i < 3) {
        parameters.emails.list[i] = $(this).val();
        i++
      }

    })
        
    alert(JSON.stringify(parameters));