JavaScript inheritance about male-female relationships

<script>
	var boyfind = {
		name:'男朋友',
		money:10000,
		have:['机械键盘','gtx1660'],
		}
	var girlfriend = {
		name:'女朋友'
		
	}
	function extend(parent,child){
		for(var key in parent){
			if(child[key]){
				continue;
			}
			child[key]=parent[key];
		}
	}
	extend(boyfind,girlfriend);
	console.dir(girlfriend);
</script>