deep Copy Loop

deepCopyLoop.js

function deepCopyLoop(obj){
    let type = Object.prototype.toString.call(obj)
    let ret
    let SrcQuene = [];
    let DestQuene = [];
    let m = new WeakMap();
    
    switch (type) {
        case '[object Null]':
        case '[object Undefined]':
        case '[object Number]':
        case '[object String]':
        case '[object Function]':
        case '[object Symbol]':
            ret = obj;
            break;
        case '[object Date]':
            ret = new Date(obj)
            break
        case '[object RegExp]':
            ret = new RegExp(obj);
            break
        case '[object Array]':
            ret = [];
            SrcQuene.push(obj);
            DestQuene.push(ret);
            m.set(obj, ret)
            break
        case '[object Object]':
            ret = {}
            SrcQuene.push(obj);
            DestQuene.push(ret);
            m.set(obj, ret)
            break
        default:
            ret = obj
    }

    while (SrcQuene.length > 0 && DestQuene.length > 0) {
        src = SrcQuene.shift();
        dest = DestQuene.shift();
        for (let key in src) {
            if (src.hasOwnProperty(key)){
                let val = src[key]
                if (m.has(val)) {
                    dest[key] = m.get(val);
                    break
                }
                let type = Object.prototype.toString.call(val)
                switch (type) {
                    case "[object Array]":
                        SrcQuene.push(val);
                        dest[key] = []
                        DestQuene.push(dest[key]);
                        break;
                    case "[object Object]":
                        SrcQuene.push(val);
                        dest[key] = {};
                        DestQuene.push(dest[key]);
                        break;
                    case '[object Null]':
                    case '[object Undefined]':
                    case '[object Number]':
                    case '[object String]':
                    case '[object Function]':
                    case '[object Symbol]':
                    case '[object Symbol]':
                        dest[key] = val;
                        break;
                    case '[object Date]':
                        dest[key] = new Date(val)
                        break
                    case '[object RegExp]':
                        dest[key] = new RegExp(val)
                        break
                    default:
                        dest[key] = val
                }
            }
        }
    }
    return ret
}