Question

我有一个在这样的路由commitments/:id上打开的页面。我想按ID显示属于该特定页面的报告的日期。但是我收到一条消息，指出无法读取属性“ commitment_id”：

错误TypeError：无法读取未定义的属性'commitment_id'

评估时（commitment.component.ts：88）

在Array.filter（）

在SafeSubscriber.eval [作为_next]（commitment.component.ts：87）

在SafeSubscriber .__ tryOrUnsub（Subscriber.js：239）

在SafeSubscriber.next（Subscriber.js：186）

在Subscriber._next（Subscriber.js：127）

在Subscriber.next（Subscriber.js：91）

在CatchSubscriber.Subscriber._next（Subscriber.js：127）

在CatchSubscriber.Subscriber.next（Subscriber.js：91）

在MapSubscriber._next（map.js：85）

ts：

    commitments: Array<Commitment>;
    selectedCommitment = null;
    reportingDates: Array<ReportingDate>;
    filteredReportingDates = [];
    id: number;
    routeId: any;
    public errorMsg;

    ngOnInit() {
        this.routeId = this.route.params.subscribe(
          params => {
            this.id = +params['id'];
          }
        )
        let commitmentRequest = this.route.params
          .flatMap((params: Params) =>
            this.servCommitment.getCommitment(+params['id' ]));
        commitmentRequest.subscribe(response => this.commitment = response.json(), error => this.errorMsg = error);

    }

  @Input() commitment: Commitment;

    onSelectedReportingDate(commitmentId) {
        this.selectedCommitment = this.commitments.find(
          (el) => {
            return el.commitment_id === commitmentId
          }
        );

        this.servReportingDate.getReportingDates().subscribe(
          reportingDate => {
            this.reportingDates = reportingDate;
            this.filteredReportingDates = this.reportingDates.filter(
              (reportingDate) => reportingDate.l_commitments_id === this.selectedCommitment.commitment_id
            );
          }
        );
    }

html：

<div *ngIf="commitment">
 <button type="submit" class="btn btn-info btn-simple" (click)="onSelectedReportingDate(commitment.commitment_id)">Test</button>
  <div *ngIf="selectedLiability">
   <div *ngFor="let reportingDate of filteredReportingDates">
        {{ reportingDate.reportingdate_plan }}
   </div>
  </div>
</div>

第87-88-89行：

  this.filteredReportingDates = this.reportingDates.filter(
    (reportingDate) => reportingDate.l_commitments_id === this.selectedCommitment.commitment_id
  );

Answer 1

您只需要对变量this.selectedCommitment进行null或未定义检查即可。

@Sachila Ranawaka代码的小修改：

(reportingDate) => this.selectedCommitment && (reportingDate.l_commitments_id === this.selectedCommitment.commitment_id)

Answer 2

检查变量中是否存在commitment_id

(reportingDate) => this.selectedCommitment && (reportingDate.l_commitments_id === this.selectedCommitment.commitment_id)

无法读取未定义的属性“ commitment_id”

2 个答案: