function go(options) {
let {speed = 4,
enable: {hyperdrive = false,
frobnifier = true}} = options;
console.log("speed=", speed,
"hyperdrive:", hyperdrive,
"frobnifier:", frobnifier);
}
go({speed: 5});

var callbacks = [];
for (var i = 0; i < 10; i++) {
callbacks.push(function() { console.log(i) })
}
callbacks[2]();