AngularJS - 访问服务对象的JS对象名称/值对时的TypeError

Question

为什么表达式databaseService[user1Constant].accountBalance会产生以下错误？

angularJsApplicationController.js：

app.controller("angularJsController", function ($scope, $location, $http, user1Constant, user2Constant, databaseService) {
    databaseService[user1Constant+'Request'].done(function(){
        console.log(JSON.stringify(databaseService));
        console.log(user1Constant);
        console.log(databaseService);
        console.log(databaseService[user1Constant]);
        console.log(databaseService[user1Constant].accountBalance);
    });
});

这是我创建对象的代码： angularJsApplication.js：

app.service("databaseService", ["user1Constant","user2Constant", function (user1Constant, user2Constant) {
    var returnObject = {};
    returnObject.updateAllEntriesUser = function (user) {

        //jQuery AJAX HTTP method
        $.post("getEntriesFromUser.php", {
            user: user
        })
            .done(function (response) {
                response = JSON.parse(response);
                returnObject[user]={};
                returnObject[user].bookings = response;
                var totalAmount = 0;
                for (var i = 0; i < response.length; i++) {
                    totalAmount += parseFloat(response[i].amount_before_comma + '.' + response[i].amount_after_comma);
                }
                returnObject[user].accountBalance = totalAmount;
            });
    };
    returnObject[user1Constant + 'Request'] = returnObject.updateAllEntriesUser(user1Constant);
    returnObject[user1Constant + 'Request'] = returnObject.updateAllEntriesUser(user2Constant);
    return returnObject;
}]);

Answer 1

控制台向您显示请求完成后当前的对象状态，这与您将其写入控制台时的状态不同。您的控制器正在尝试在加载数据之前访问数据，这就是您的用户数据没有您期望的属性的原因。

您需要从服务中返回一个jQuery延迟对象，然后将一个函数传递给它的 ► iMac@~:brew info openssl openssl: stable 1.0.2h (bottled) [keg-only] SSL/TLS cryptography library https://openssl.org/ /usr/local/Cellar/openssl/.openssl (8B) Poured from bottle on 2016-02-15 at 21:07:44 /usr/local/Cellar/openssl/1.0.2f (1,651 files, 11.9M) Poured from bottle on 2016-02-15 at 21:07:44 /usr/local/Cellar/openssl/1.0.2g (1,678 files, 12.0M) Poured from bottle on 2016-03-07 at 18:32:36 /usr/local/Cellar/openssl/1.0.2h (1,691 files, 12M) Poured from bottle on 2016-05-07 at 21:17:01 /usr/local/Cellar/openssl/1.0.2h_1 (1,691 files, 12M) Poured from bottle on 2016-05-12 at 23:09:46 From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/openssl.rb 函数，以便您可以等到获取数据直到它被加载。

或者你可以欺骗并使用$ scope。$ watch ...

您可以将其更改为更灵活，但要使其使用最少量的更改：

done

你的控制器：

app.service("databaseService", ["user1Constant","user2Constant", function (user1Constant, user2Constant) {
  var returnObject = {};
  returnObject.updateAllEntriesUser = function (user) {

    //jQuery AJAX HTTP method
    return $.post("getEntriesFromUser.php", {
        user: user
    })
        .done(function (response) {            
            response = JSON.parse(response);
            returnObject[user]={};
            returnObject[user].bookings = response;
            var totalAmount = 0;
            for (var i = 0; i < response.length; i++) {
                totalAmount += parseFloat(response[i].amount_before_comma + '.' + response[i].amount_after_comma);
            }
            returnObject[user].accountBalance = totalAmount;
        });
  }

  returnObject[user1Constant + 'Request'] = returnObject.updateAllEntriesUser(user1Constant);
  returnObject[user2Constant + 'Request'] = returnObject.updateAllEntriesUser(user2Constant);
  console.log(returnObject); //angularJsApplication.js:101
  return returnObject;
});