带有 async/await 失败的 Angular 承诺

Question

到目前为止，我所看到的解决我问题的建议似乎并不适用，或者我有一个很大的误解（我已经有一段时间没有接触过完整的堆栈了）。我有一项服务成功地访问了 Spring Boot 后端以获取进程列表：

function getReportProcesses(){
        var deferred =  $q.defer();
        var url = "fermentationReports/processes";
        httpService.get(url).then(function (data){
            deferred.resolve(data);
        }, function(msg){
            var errMsg  = "failed to get report processes: " +  msg;
            deferred.reject(errMsg);
        });
        return deferred.promise;
    }

我的目标是从下拉工厂中获取服务，将列表转换为 JSON，并将其传递给由下拉指令填充的下拉列表。当指令调用以下行来获取 JSON 时：

var data = ReportDdlFactory.getReportName();
            addAllTo(data, $scope.addAll);

在将data 作为undefined 添加到范围之前，它不会等待getReportName() 中的httpService 返回。这是工厂中的原始方法：

function getReportName() {

            try {
                FermentationReportsService.getReportProcesses().then(function (data) {
                    if (data.processes !== undefined) {

                        var output = {"data": []};
                        for (var i = 0; i < data.processes.length; i++) {
                            var currentLine = {"value": data.processes[i], "label": data.processes[i]};
                            output.data.push(currentLine);
                        }
                        return output;

                    } else {
                        return {
                            "data": [
                                {"value": "ERROR OBTAINING PROCESSES", "label": "ERROR OBTAINING PROCESSES"}]
                        };
                    }
                });
            } catch (err) {
                console.log("error caught: " + err);
            }
        }

我尝试将其更改为使用 async/await，因为 getReportProcesses() 已经返回了一个承诺：

async getReportName() {

            try {
                await FermentationReportsService.getReportProcesses().then(function (data) {
                    if (data.processes !== undefined) {

                        var output = {"data": []};
                        for (var i = 0; i < data.processes.length; i++) {
                            var currentLine = {"value": data.processes[i], "label": data.processes[i]};
                            output.data.push(currentLine);
                        }
                        return output;

                    } else {
                        return {
                            "data": [
                                {"value": "ERROR OBTAINING PROCESSES", "label": "ERROR OBTAINING PROCESSES"}]
                        };
                    }
                });
            } catch (err) {
                console.log("error caught: " + err);
            }
        }

但我总是从 jshint 得到这个：

 14 |            async getReportName() {
                 ^ Expected an assignment or function call and instead saw an expression.
 14 |            async getReportName() {
                      ^ Missing semicolon.
 14 |            async getReportName() {
                                      ^ Missing semicolon.
 17 |                    await FermentationReportsService.getReportProcesses().then(function (data) {
                         ^ Expected an assignment or function call and instead saw an expression.
 17 |                    await FermentationReportsService.getReportProcesses().then(function (data) {
                              ^ Missing semicolon.
  8 |                getReportName: getReportName,
                                    ^ 'getReportName' is not defined.
 14 |            async getReportName() {
                       ^ 'getReportName' is not defined.
 14 |            async getReportName() {
                 ^ 'async' is not defined.

我觉得我可能比需要的更难，或者我错过了一些简单的东西？

---

编辑：

经过更多研究，我确定应用程序以 'strict' 运行，强制 ECMA 5。有没有一种方法可以在不使用 ES6 方法的情况下强制响应？

Answer 1

我可能会这样做：

function getReportName() {
  return FermentationReportsService
    .getReportProcesses()
    .then(function(data) {
      if (data.processes === undefined) {
        return { data: [
          { value: "ERROR OBTAINING PROCESSES", label: "ERROR OBTAINING PROCESSES" }
        ]};
      }
      
      return {
        data: data.processes.map(function(process) {
                return { value: process.value, label: process.value };
              })
      };
    })
    .catch(function(err) {
      console.log("error caught: " + err);
    });
}

Answer 2

通过使用 async/await，您不再需要使用 then

async function getReportName() {
  try {
    const data = await FermentationReportsService.getReportProcesses();
    if (data.processes !== undefined) {
      var output = { data: [] };
      for (var i = 0; i < data.processes.length; i++) {
        var currentLine = {
          value: data.processes[i],
          label: data.processes[i],
        };
        output.data.push(currentLine);
      }
      return output;
    } else {
      return {
        data: [
          {
            value: 'ERROR OBTAINING PROCESSES',
            label: 'ERROR OBTAINING PROCESSES',
          },
        ],
      };
    }
  } catch (err) {
    console.log('error caught: ' + err);
  }
}

查看这篇文章了解更多信息?javascript.info async/await