高德地图获取当前城市

<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <title>高德地图获取当前城市</title>
    <script type="text/javascript" src="http://webapi.amap.com/maps?v=1.4.15&key=943991f38e4aec19029d284ff4ffac9c&plugin=AMap.CitySearch"></script>
</head>
<body>
<div id="tip"></div>
<script type="text/javascript">
	//异步方法
	Promise.prototype.finally = function (callback) {
		var P = this.constructor;
		return this.then(
			function(value){
				P.resolve(callback()).then(function(){
					return value
				})
			},
			function(reason){
				P.resolve(callback()).then(function(){
					throw reason
				})
			}
		);
	};
    //获取用户所在城市信息
    function showCityInfo() {
		return new Promise(function (resolve, reject) {
			var res;
			//实例化城市查询类
	        var citysearch = new AMap.CitySearch();
	        //自动获取用户IP，返回当前城市
	        citysearch.getLocalCity(function(status, result) {
	            if (status === 'complete' && result.info === 'OK') {
	                if (result && result.city && result.bounds) {
	                    var cityinfo = result.city;
	                    var citybounds = result.bounds;
	                    res = cityinfo;
	                }
	            } else {
	                res = result.info;
	            }
				resolve(res);
	        });
		});
    }
    showCityInfo().then(function(res){
		console.log('当前城市->',res);
	});
</script>
</body>
</html>