map-speed, the JS version

function fmt_bytenum( n )
{
    var on = n;
    var i = 0;
    var units = [ "B", "kB", "MB" ];
    while( n > 2048 && i < units.length - 1 )
    {
        n /= 1024;
        i++;
    }
    return n + " " + units[i] + " (" + on + " bytes)";
}

function printlns()
{
    for(var i = 0; i < arguments.length; i++)
        console.log(arguments[i]);
}

function ftime(){ return (new Date()).getTime() / 1000; }
function sys_stat(){ return 0; }

var count = 100000;

mem_base = sys_stat(3);
num_base = sys_stat(6);
obj = new Map();
t0 = ftime();
for( var i = 0; i < count; ++i )
    obj.set( i, ftime() );
mem_load = sys_stat(3);
num_load = sys_stat(6);

t1 = ftime();
for( var i = 0; i < count; ++i )
    dummy = obj.get( i );

t2 = ftime();
for( var i = 0; i < count; ++i )
    obj.delete( i );
mem_unload = sys_stat(3);
num_unload = sys_stat(6);

t3 = ftime();

obj = null;
mem_free = sys_stat(3);

printlns( "-- info --", "count: " + count );
printlns( "-- time --", "set: " + (t1-t0), "get: " + (t2-t1), "unset: " + (t3-t2) );