Question

这个小函数应该在逻辑上总是返回，但我得到了未定义： -

    function hasAccess() {
            var dataObj = {
                    "id" : $scope.groupId
                };
            $http.post('http://vlinux:9099/GetItems', dataObj).then(
                    function(response) {
                        var result = response.data.result;
                            if(result.includes($scope.screenId)) {
                                return "ok";
                            } else {
                                return "nok";
                            }
                    });
        }

我开始得到downvotes，所以wuickly添加，我调试了它，看到http调用带来了预期的响应，并且流程正在向右跳转if / else阻止。问题是当我在变量中调用此函数时，它存储未定义。

电话也很简单： -

    var allow = hasAccess();

Answer 1

$ http.post不是同步的，而是异步的。因此，$ http.post之后的所有内容都是一个承诺，而不是您期望的布尔值。

documentation显示如何提供＆＃34;回调＆＃34;在成功和失败的情况下，你的职能：

// Simple GET request example:
$http({
  method: 'GET',
  url: '/someUrl'
}).then(function successCallback(response) {
    // this callback will be called asynchronously
    // when the response is available
    // for example : manageWHenOk
  }, function errorCallback(response) {
    // called asynchronously if an error occurs
    // or server returns response with an error status.
   // for example : manageWHenKO
  });

Answer 2

只有在请求正常时，您的函数才会返回结果。如果有错误，您的功能什么都不做！我建议你添加一个catch函数。

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg" id="svg1" version="1.1" viewBox="49.595489 30.040314 84.135223 84.305336" height="84.305336mm" width="84.135223mm">
    	
    	
    	<defs>
    		<style>
    			.logo{
    				stroke-dasharray: 800;
    				stroke-dashoffset: 0;
    				animation: dash 2s linear forwards;			
    			}
    			
    			@keyframes dash {
    				from {
    					stroke-dashoffset: 800;
    				}
    				to {
    					stroke-dashoffset: 0;
    				}
    			}
    		</style>
    	</defs>
    	
      <path class="logo"
         id="logo"
         d="m 70.303571,78.340773 c -4.032971,0.006 -8.033187,1.698025 -10.862132,4.572387 -2.828946,2.874362 -4.455685,6.891674 -4.445904,10.924637 0.0095,3.927963 1.572604,7.841853 4.315065,10.653953 2.74246,2.8121 6.641232,4.47709 10.569138,4.45364 4.633366,-0.0277 9.108311,-2.43049 12.384652,-5.70683 3.574526,-3.57453 6.411017,-6.242046 9.347584,-9.825986 0,0 7.17598,-6.918764 10.743336,-10.51178 3.56737,-3.593016 7.41006,-7.169152 11.08478,-10.843875 3.34645,-3.346446 6.32139,-6.581106 9.51049,-9.812482 3.3753,-3.420038 5.15813,-7.12199 5.18334,-11.661986 0.0216,-3.889398 -1.60848,-8.155743 -4.38434,-10.880165 -2.77587,-2.724421 -6.6563,-4.279784 -10.54572,-4.261811 -3.8759,0.01791 -7.72562,1.595418 -10.48769,4.314587 -2.762056,2.71917 -5.002206,6.149863 -4.776456,11.428746 -0.0484,4.514439 2.874106,9.098792 5.148056,11.372746 3.19237,3.192372 6.9848,6.227335 10.17717,9.419709 3.20164,3.201638 6.0452,5.990107 9.58187,9.526778 1.80732,1.807321 3.93629,5.149881 4.68721,7.593023 0.75092,2.443141 1.01197,5.054051 0.5999,7.576553 -0.55185,3.378163 -2.33545,6.072793 -4.93781,8.296363 -2.60235,2.22358 -5.80201,3.69214 -9.22483,3.7206 -4.69281,0.039 -9.04011,-1.51725 -12.0905,-4.81311 -3.187696,-3.44421 -7.211206,-7.037566 -10.268806,-10.463896 -3.057595,-3.42633 -6.28628,-6.607684 -9.408672,-9.762441 -3.174881,-3.207791 -7.386446,-5.316042 -11.899731,-5.30936 z"
    		
         style="fill:none;fill-opacity:1;stroke:#febc00;stroke-width:10.80000019;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-opacity:1" />
    
    </svg>

如果仍然未定义，则意味着在获取响应之前加载了模板。为了解决这个问题，你可以在$ stateProvider的resolve方法中执行请求。

始终返回函数返回undefined

2 个答案: