What is the cleanest method for conditional statements in Javascript?

I am just thinking about best solution for situation when you have to initialize some variable and the "if something" update it. What way should I use and why?

let someObj = {};
if(localStorage.getItem('someData')) {
    someObj = JSON.parse(localStorage.getItem('someData'));
}

let someObj = {};
if(localStorage.getItem('someData')) someObj = JSON.parse(localStorage.getItem('someData'));

if(localStorage.getItem('someData')) {
    someObj = JSON.parse(localStorage.getItem('someData'));
} else {
    let someObj = {};
}

Or maybe some other propositions?