js map
productSkuMap
_this.scanCdItems = new Map()
_this.scanCdItems.delete(item);
tmpCdItems.set(item[0],item[1]);
if (tmpCdItems.has(item)) {
for(var item of _this.scanCdItems)
scanCdItems.size
for(var key in _this.scanCdItems)
tmpCdItems.get(key)
tmpCdItems.get(noExistsKey) == undefined