JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" checked="checked" value="1" />
<input type="checkbox" checked="checked" value="2" />
<input type="checkbox" checked="checked" value="3" />

JavaScript

var reasons = $('input:checked').map(function() {
    return $(this).val();
});
console.log(reasons);

var reasonsWithGet = $('input:checked').map(function() {
    return $(this).val();
}).get();
console.log(reasonsWithGet);