事情是这样的:我有一个 HTTP get 请求,它返回一个 JSON 对象列表。我使用 RxJS 订阅接收该列表的数据。现在,对于该列表中的每个对象,我想执行另一个 HTTP 请求,然后将该请求的结果放入数组中。
到目前为止,我已经能够做到这一点,但我似乎无法弄清楚如何维护数据初始列表的顺序。这可能与整个 Observable 机制是异步的有关。
这是我的代码:
ngOnInit(): void {
this.shiftInformationService.getShifts("2016-11-03T06:00:00Z", "2016-11-06T06:00:00Z")
.subscribe(shifts => {
shifts.forEach(shift => {
this.addDataToAreaChart(shift.startDateTime, shift.endDateTime, shift.description);
});
});
}
addDataToAreaChart(startDate: string, endDate: string, description: string) {
this.machineStatisticsService
.getCumulativeMachineStateDurations(startDate, endDate)
.subscribe(s => {
this.areaChartData = [];
this.areaChartData.push(new AreaChartData(startDate, endDate, description, s));
});
}
我想要的是维持从调用的顺序shifts.forEach
推送数据时循环areaChartData
array.
有任何想法吗?帮助将不胜感激!
更新:已解决!
最终代码:
ngOnInit(): void {
var startDate = new Date();
startDate.setDate(startDate.getDate() - 3);
this.shiftInformationService.getShifts(DateUtil.formatDate(startDate), DateUtil.formatDate(new Date()))
.subscribe(shifts => {
Observable.from(shifts)
.concatMap((shift) => {
return this.machineStatisticsService
.getCumulativeMachineStateDurations(shift.startDateTime, shift.endDateTime)
.map((result) => {
return {
"addDataToAreaChartValue": result,
"shift": shift
}
});
})
.subscribe(s => {
this.areaChartData = [];
this.areaChartData.push(
new AreaChartData(
s.shift.startDateTime,
s.shift.endDateTime,
s.shift.description + ' ' + s.shift.startDateTime.slice(5, 10),
s.addDataToAreaChartValue
)
);
});
});
}
感谢迈克尔!