js object clear
// for enumerable and non-enumerable of an object with proto chain
var props = Object.getOwnPropertyNames(obj);
for (var i = 0; i < props.length; i++) {
delete obj[props[i]];
}
// for enumerable properties of shallow/plain object
for (var key in obj) {
// this check can be safely omitted in modern JS engines
// if (obj.hasOwnProperty(key))
delete obj[key];
}