let, var and const

function outer_func()
{
    {{
        var var01 = "var01";
        let innerLet = "innerLet";//        const innerCst = "innerCst";

        function inner_func()
        {
            alert("inner_func");
        }
    }}
    // var01 is accessible here
    // it's an early error to access innerLet here

    inner_func();
}

outer_func();