JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" class="check">Item 1
<input type="checkbox" class="check">Item 2
<input type="checkbox" class="check">Item 3
<input type="checkbox" class="check">Item 4
<input type="checkbox" class="check">Item 5
<br>
<br>
<button class="sendform">Disparar Ação do form</button>

JavaScript

checkChecks('.check', '.sendform');

$('.check').on('change', function () {
    checkChecks('.check', '.sendform');
});

function checkChecks(selector, buttonToDisable) {
    var s = $(selector + ':checked'),
        b = $(buttonToDisable);
    if (s.length < 1) {
        b.prop('disabled', true);
    } else {
        b.prop('disabled', false);
    }
}