角度4中显示的日期落后一个月

角度4中显示的日期落后一个月
启动日历添加 2018-04-30 &显示 {3/30/2018}

Html文件:

<div class="col-md-8 noPadding">
        <p-calendar dataType="date" name="PublishDate" [ngModelOptions]="{utc: 
            'true'}" [ngModel]="resource.PublishDate | date:'yyyy-MM-dd'" 
            (ngModelChange)="resource.PublishDate = $event" showOtherMonths="true" 
            dateFormat="yy-mm-dd" [showIcon]="true"></p-calendar>
</div>

类型脚本:

update() {
                this.loading = true;
                this.publishDate  = this.resource.PublishDate.getMonth() + '-' + this.resource.PublishDate.getDate() + '-' + this.resource.PublishDate.getFullYear();

               this.resource.PublishDate = this.publishDate
                let data = JSON.stringify(this.resource); 


                this.resourceService.putForm('Resource').subscribe((response: any) => {
                    detail: 'Resource is Updated' });
                }, (error: any) => {

                });
            }