Binding localStorage API to extend the key -> value functionnality with JSON api

localStorage.js

/**
* @author : Purexo
* @description : Binding localStorage API to extend the key -> value functionnality with JSON api
*                when setItem, data is stringify
*                when getItem, data is parsed
* @usage :
*   ls.setItem('key', data)
*   ls.getItem('key', data)
*   ls.removeItem('key')
*   ls.key('index')
*   ls.clear()
*/
let ls;
(function() {
    function LS () { }
    LS.prototype.setItem = (key, data) => {
        return localStorage.setItem(key, JSON.stringify(data));
    }
    LS.prototype.getItem = (key) => {
        return JSON.parse(localStorage.getItem(key));
    }
    LS.prototype.removeItem = (key) => {
        return localStorage.removeItem(key);
    }
    LS.prototype.key = (index) => {
        return localStorage.key(index);
    }
    LS.prototype.clear = () => {
        return localStorage.clear();
    }
    ls = new LS();
})();