<label>Option 1<input type="checkbox" name="opt1"></label>
<label>Option 2<input type="checkbox" name="opt2" checked></label>
<label>Option 3<input type="checkbox" name="opt3"></label>
<label>Option 4<input type="checkbox" name="opt4" checked></label>
<button>Read localStorage</button>

localStorage.clear();

let c = document.querySelectorAll("input");
c.forEach((item) => localStorage.setItem(item.name, item.checked));

document.querySelector("button").addEventListener("click", readStore);

function readStore() {
  for (const [key, value] of Object.entries(localStorage)) {
    if(value=='true') console.log(`${key}: ${value}`);
  }
}