Question

我有一个非常复杂且庞大的数据，我必须在组件中围绕它构建一个Reactive表单。

我已经开发了表格。但是，当我在input字段之一中键入内容以编辑填充的数据时，它在更新该字段的值时响应非常慢。

我尝试使用updateOn:'blur'和'submit'，但没有任何运气。

我的问题是，处理具有大数据的表单的最佳实践是什么？

更新：这是我的StackBlitz。

注意：我已经为实际实现创建了一个非常小的版本，并且在反应式表单中存在性能问题。

Answer 1

因此，在与您的StackBlitz玩了大约一天之后，我在这里提出了解决方案。我认为这将大大提高性能。

步骤1：为数据模型创建接口

这样做将大大提高代码的清晰度和可读性。这也将使代码更易于管理且易于使用。因此，我们为您的特定情况列出了interface的列表：

export interface Hotel {
  id: string;
  currencyId: string;
  hotelYearId: string;
  priceTaxTypeId: string;
  code: string;
  name: string;
  createBy: string;
  createDate: string;
  lastUpdateBy: string;
  lastUpdateDate: string;
  remark: string;
  internalRemark: string;
  roomTypes: RoomType[];
}

export interface RoomType {
  chk: boolean;
  roomTypeId: string;
  mealTypes: MealType[];
}

export interface MealType {
  chk: boolean;
  mealTypeId: string;
  marketGroups: MarketGroup[];
}

export interface MarketGroup {
  chk: boolean;
  markets: Market[];
  rateSegments: RateSegment[];
}

export interface Market {
  marketId: string;
}

export interface RateSegment {
  chk: boolean;
  rateSegmentId: string;
  hotelSeasons: HotelSeason[];
}

export interface HotelSeason {
  chk: boolean;
  hotelSeasonId: string;
  rates: Rate[];
}

export interface Rate {
  rateCodeId: string;
  cancellationPolicyId: string;
  dayFlag: string;
  singlePrice: string;
  doublePrice: string;
  xbedPrice: string;
  xbedChildPrice: string;
  bfPrice: string;
  bfChildPrice: string;
  unitMonth: string;
  unitDay: string;
  minStay: number;
}

步骤2：更改创建表单的方式

创建表单的方式非常嘈杂。有一个明确的方法。而且，由于您已经在服务中创建了表单，因此建议您保留为服务本身创建表单的任务，并使组件不受任何此类任务的影响。因此，您的服务可以像这样重构：

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { FormBuilder, Validators } from '@angular/forms';
import { map } from 'rxjs/operators';

import { Hotel, RoomType, MealType, MarketGroup, Market, RateSegment, HotelSeason, Rate } from './hotel.model';

@Injectable()
export class UtilService {

  constructor(
    private readonly fb: FormBuilder,
    private readonly http: HttpClient
  ) { }

  getHotelForm() {
    return this.getHotel().pipe(
      map((apiResponse: any) => this.fb.group({
        id: [apiResponse.id, Validators.required],
        currencyId: [apiResponse.currencyId, Validators.required],
        hotelYearId: [apiResponse.hotelYearId, Validators.required],
        priceTaxTypeId: [apiResponse.priceTaxTypeId, Validators.required],
        code: [apiResponse.code, Validators.required],
        name: [apiResponse.name, Validators.required],
        createBy: [apiResponse.createBy, Validators.required],
        createDate: [apiResponse.createDate, Validators.required],
        lastUpdateBy: [apiResponse.lastUpdateBy, Validators.required],
        lastUpdateDate: [apiResponse.lastUpdateDate, Validators.required],
        remark: [apiResponse.remark, Validators.required],
        internalRemark: [apiResponse.internalRemark, Validators.required],
        roomTypes: this.fb.array(apiResponse.roomTypes.map(roomType => this.generateRoomTypeForm(roomType)))
      }))
    );
  }

  private getHotel() {
    return this.http.get('/assets/hotel.json');
  }

  private generateRoomTypeForm(roomType: RoomType) {

    const roomTypeForm = this.fb.group({
      chk: [roomType.chk, Validators.required],
      roomTypeId: [roomType.roomTypeId, Validators.required],
      mealTypes: this.fb.array(roomType.mealTypes.map(mealType => this.generateMealTypeForm(mealType)))
    });

    return roomTypeForm;
  }

  private generateMealTypeForm(mealType: MealType) {

    const mealTypeForm = this.fb.group({
      chk: [mealType.chk, Validators.required],
      mealTypeId: [mealType.mealTypeId, Validators.required],
      marketGroups: this.fb.array(mealType.marketGroups.map(marketGroup => this.generateMarketGroupForm(marketGroup)))
    });

    return mealTypeForm;
  }

  private generateMarketGroupForm(marketGroup: MarketGroup) {

    const marketGroupForm = this.fb.group({
      chk: [marketGroup.chk, Validators.required],
      markets: this.fb.array(marketGroup.markets.map(market => this.generateMarketForm(market))),
      rateSegments: this.fb.array(marketGroup.rateSegments.map(rateSegment => this.generateRateSegmentForm(rateSegment))),
    });

    return marketGroupForm;
  }

  private generateMarketForm(market: Market) {
    return this.fb.group({
      marketId: [market.marketId, Validators.required]
    });
  }

  private generateRateSegmentForm(rateSegment: RateSegment) {
    const rateSegmentForm = this.fb.group({
      chk: [rateSegment.chk, Validators.required],
      rateSegmentId: [rateSegment.rateSegmentId, Validators.required],
      hotelSeasons: this.fb.array(rateSegment.hotelSeasons.map(hotelSeason => this.generateHotelSeasonForm(hotelSeason)))
    });

    return rateSegmentForm;
  }

  private generateHotelSeasonForm(hotelSeason: HotelSeason) {

    const hotelSeasonForm = this.fb.group({
      chk: [hotelSeason.chk, Validators.required],
      hotelSeasonId: [hotelSeason.hotelSeasonId, Validators.required],
      rates: this.fb.array(hotelSeason.rates.map(rate => this.generateRateForm(rate)))
    });
    return hotelSeasonForm;
  }

  private generateRateForm(rate: Rate) {
    return this.fb.group({
      rateCodeId: [rate.rateCodeId, Validators.required],
      cancellationPolicyId: [rate.cancellationPolicyId, Validators.required],
      dayFlag: [rate.dayFlag, Validators.required],
      singlePrice: [rate.singlePrice, Validators.required],
      doublePrice: [rate.doublePrice, Validators.required],
      xbedPrice: [rate.xbedPrice, Validators.required],
      xbedChildPrice: [rate.xbedChildPrice, Validators.required],
      bfPrice: [rate.bfPrice, Validators.required],
      bfChildPrice: [rate.bfChildPrice, Validators.required],
      unitMonth: [rate.unitMonth, Validators.required],
      unitDay: [rate.unitDay, Validators.required],
      minStay: [rate.minStay, Validators.required]
    });
  }

}

步骤3：利用以上服务：

执行此操作以获取表单并摆脱methods，该模板会返回给您FormArray。这将使您的组件非常干净，清晰和简洁。

import { Component, ChangeDetectionStrategy } from '@angular/core';
import { FormGroup } from '@angular/forms';
import { Observable } from 'rxjs';

import { UtilService } from '../app/util.service';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
  changeDetection: ChangeDetectionStrategy.OnPush
})

export class AppComponent {

  form$: Observable<FormGroup> = this.util.getHotelForm();

  constructor(private readonly util: UtilService) {
  }

}

第4步：重构模板：

这是最重要的。从不以深度嵌套的形式调用获取器或方法来获取FormArray。或者更确切地说，以一般形式或在数据绑定语法内部。因为它们会在每个更改检测周期中被调用，并且会破坏您应用的性能。

请参阅this lightning talk by Tanner Edwards from ng-conf 2018以了解更多信息。

因此，您可以像这样重构组件模板：

<form 
  *ngIf="form$ | async as form" 
  [formGroup]="form">
    <div 
    formArrayName="roomTypes">
        <div 
      *ngFor="let roomType of form.controls['roomTypes'].controls; let index = index" 
      [formGroupName]="index">
            {{index}}
            <div 
        formArrayName="mealTypes">
                <div 
          *ngFor="let mealType of roomType.controls['mealTypes'].controls; let mealtypeIndex = index"
          [formGroupName]="mealtypeIndex">
                    mealtype {{mealtypeIndex}}
                    <div 
            formArrayName="marketGroups">
                        <div 
              *ngFor="let marketGroup of mealType.controls['marketGroups'].controls; let marketGroupIndex = index" 
              [formGroupName]="marketGroupIndex">
                            marketGroupIndex {{marketGroupIndex}}
                            <div formArrayName="rateSegments">
                                <div 
                  *ngFor="let rateSegment of marketGroup.controls['rateSegments'].controls; let rateSegmentIndex = index"
                  [formGroupName]="rateSegmentIndex">
                                    rateSegmentIndex {{rateSegmentIndex}}
                                    <div formArrayName="hotelSeasons">
                                        <div 
                      class="fifth_border" 
                      *ngFor="let hotelseason of rateSegment.controls['hotelSeasons'].controls; let hotelseasonIndex = index"
                      [formGroupName]="hotelseasonIndex">
                                            hotelseasonIndex {{hotelseasonIndex}}
                                            <div formArrayName="rates">
                                                <div 
                          *ngFor="let rate of hotelseason.controls['rates'].controls; let rateIndex = index"
                          [formGroupName]="rateIndex">
                          <div style="display:flex;flex-flow;row">
                            <div>
                              <p>SGL</p>
                              <input class="input text_right" type="text" formControlName="singlePrice">
                            </div>
                            <div>
                              <p>DLB/TWN</p>
                              <input class="input text_right" type="text"  formControlName="doublePrice">
                            </div>
                            <div>
                              <p>EX-Adult</p>
                              <input class="input text_right" type="text"  formControlName="xbedPrice" >
                            </div>
                            <div>
                              <p>EX-Child</p>
                              <input class="input text_right" type="text"  formControlName="xbedChildPrice">
                            </div>
                            <div>
                              <p>Adult BF</p>
                              <input class="input text_right" type="text"  formControlName="bfPrice">
                            </div>
                            <div>
                              <p>Child BF</p>
                              <input class="input text_right" type="text"  formControlName="bfChildPrice">
                            </div>
                          </div>
                        </div>
                      </div>
                    </div>
                  </div>
                </div>
              </div>
            </div> 
          </div>
        </div>
      </div>
    </div>
  </div>
  <!-- <pre>{{form.value | json}}</pre> -->
</form>

第5步：不要在这里停止

这还没有结束。这仅仅是个开始。您还可以将子窗体（marketGroup FormGroup内的marketGroups FormArray）抽象为一个单独的组件。然后可以将其changeDetectionStrategy设置为OnPush。这样可以为您带来更好的性能。

这里是您可以参考的 StackBliz ，以了解该解决方案。

执行所有这些操作将显着提高表单的性能。

我希望这会有所帮助。如果我发现其他可以提高性能超出此限制的东西，我将尝试更新此答案。

这是您推荐的Working Sample StackBlitz。

这是我为Detailed Medium Article写的AngularInDepth。

性能差异

我刚刚对您的实施以及我在应用程序上执行的相同步骤进行了绩效审核。

Angular 7，大数据时反应形式响应缓慢

1 个答案: