范围变量undefined在.then`方法之外 [英] scope variable undefined outside `.then` method

问题描述

我在if语句中更改了scope变量，在if语句之外更改了一个未定义的变量

I changed the scope variable in an if statement and outside the if statement it turned into an undefined variable

app.controller("Login", function($scope, $window,$http){
    var status;
    $scope.loginUser = function(logData){
        $http.post('/corporate/login',logData).then(function(response){
              var data = response.data
              var status = data.success;
              if(status == true){
                $scope.logStatus = true;
                console.log($scope.logStatus); // prints true
              }else{
                $scope.logStatus = false;
              }
        })

        console.log($scope.logStatus); //prints undefined
    }
});

推荐答案

外...它变成了一个未定义的变量

outside ... it turned into an undefined variable

它没有变成 undefined 价值。代码中的最后一个 console.log 在成功处理程序中的 console.log之前执行。它是 undefined ，因为它尚未由成功处理程序设置。

It did not "turn into" an undefined value. The last console.log in the code executes before the console.log in the success handler. It is undefined because it has not yet been set by the success handler.

console.log("Part1");
console.log("Part2");
var promise = $http.get(url);
promise.then(function successHandler(response){
    console.log("Part3");
});
console.log("Part4");

Part4的控制台日志不必等待数据从服务器返回。它在XHR 启动后立即执行。 Part3的控制台日志位于成功处理函数内，该函数由 $ q service 并在数据从服务器到达并且XHR 完成之后调用。

The console log for "Part4" doesn't have to wait for the data to come back from the server. It executes immediately after the XHR starts. The console log for "Part3" is inside a success handler function that is held by the $q service and invoked after data has arrived from the server and the XHR completes.

有关详细信息，请参阅如何在成功处理程序外使用$ http promise响应。

For more information, see How to use $http promise response outside success handler.

console.log("Part 1");
console.log("Part 2");
var promise = new Promise(r=>r());
promise.then(function() {
    console.log("Part 3");
});
console.log("Part *4*");

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