Faster Cloning

[splitice]

function fn(){
	
}
const CloneSymbol = Symbol()
function cloner(obj){
	obj[CloneSymbol] = ()=>{return {"_id":"ididid", v: 1, a: "abc"}}
	return obj
}
const obj = cloner({"_id":"ididid", v: 1, a: "abc"})
for(let i=0;i<1000;i++){
	fn(obj[CloneSymbol]())
}

performs at-least 10x faster than

function fn(){
	
}

function deepCopy (obj) {
  let res;

  if ( typeof obj === 'boolean' ||
       typeof obj === 'number' ||
       typeof obj === 'string' ||
       obj === null ||
       (obj instanceof Date) ) {
    return obj;
  }

  
  if (Array.isArray(obj)) {
    res = new Array(obj.length);
    for(let i = obj.length; i--;){
      res[i] = deepCopy(obj[i]);
    }
    return res;
  }


  if (typeof obj !== 'object') return undefined;   // For now everything else is undefined. We should probably throw an error instead
  
  res = {};
  for(const k in obj){
    res[k] = deepCopy(obj[k]);
  }
  return res;
}

const obj = {"_id":"ididid", v: 1, a: "abc"}
for(let i=0;i<1000;i++){
	fn(deepCopy(obj))
}

Would use 2x memory, and only make sense for read frequently databases that don't use findUnsafe or use the return value from update