搜索/过滤状态NGXS [英] Search / Filter State NGXS

问题描述

我是NGXS的新手，正在尝试将其集成到一个小型项目中.唯一的问题是，没有关于状态的搜索/过滤器的好例子.

I am new to NGXS and trying to integrate it into a small project. The only problem is that there are no good examples of a search / filter on state.

我的应用从后端API获取产品列表.在页面上按SKU显示它们.我希望用户能够在输入字段中输入SKU，并让列表根据用户类型自动过滤产品.

My app gets a list of products from a backend API. It shows them by SKU on the page. I want the user to be able to type in an SKU in the input field and have the list automatically filter products as the user types.

products.state.ts:

products.state.ts:

@Selector()
static getProductList(state: ProductStateModel) {
  return state.products;
}

@Selector()
static prodFilter(searchObj: any[]) {
  // something needs to happen here in order to filter state
}

products.component.ts:

products.component.ts:

@Select(ProductState.getProductList) products: Observable<Product[]>;

filterForm = this.fb.group({ sku: null });

constructor( private store: Store, private fb: FormBuilder ) { }

ngOnInit() {
  this.store.dispatch( new GetProducts() );
}

//something in here (ngOnInit? ngOnChanges?) to pass (cloned??) product state into selector??

products.component.html:

products.component.html:

<form
  [formGroup]='filterForm'
  novalidate
  ngxsForm='products.filterForm'
  (ngSubmit)='onSubmit()'
>
  <input type='number' formControlName='sku' />
  <button type='submit'>Submit</button>
</form>

<mat-accordion class='product-accordion'>
  <mat-expansion-panel *ngFor='let product of products | async'>
    <mat-expansion-panel-header>
      SKU: {{ product.sku }}
    </mat-expansion-panel-header>

    <p>${{ product.price }}</p>
    <p>{{ product.description }}</p>
  </mat-expansion-panel>
</mat-accordion>

我有很多问题.我认为我不应该直接改变产品状态，所以我可以克隆它吗? HTML的输出会改变吗?我应该为过滤后的产品创建一个新的state.ts文件吗?

I have so many questions. I believe that I shouldn't be mutating the products state directly so would I clone it? Would the HTML output change then? Should I create a new state.ts file for the filtered products?

任何帮助都将不胜感激(尤其是stackblitz示例)！

Any help would be much appreciated (especially a stackblitz example)!

推荐答案

如果您对状态进行如下建模，捕获基本产品列表和在搜索文本框中输入的文本，则可能会发现这更容易:

You might find this easier if you model your state like this, capturing the base products list and the text entered in the search textbox:

export interface ProductsStateModel {
  products: Product[];
  filterText: string; // Your SKU value that is entered
} 

..然后在您的状态下，使用选择器投影出您实际要在UI(filteredProducts)上显示的筛选列表.

.. Then in your state, use a selector to project out the filtered list that you actually want to display on the UI (filteredProducts).

@State<ProductsStateModel>({
 name: 'products'
})
export class ProductsState { 

   @Selector()
   static filteredProducts(state: ProductsStateModel) { 
      return state.products.filter(p => p.sku === state.filterText);
   }

   @Action(ProductSkuEntered)
   updateFilter({patchState}: StateContext<ProductStateModel>, {payload}: ProductSkuEntered) {
       patchState({ filterText: payload.skuText });
   }
..

}

在用户界面中，您可以在模板中然后订阅选择器，即在products.component.ts中使用@Select(ProductsState.filteredProducts) products$.

In the UI, you can in your template then subscribe to the selector i.e. in products.component.ts use @Select(ProductsState.filteredProducts) products$.

当搜索文本更改时，您可以向商店分派操作以更新状态为该字符串的字符串，例如store.dispatch(new ProductSkuEntered({ skuText: enteredText })); NGXS选择器随后将自动更新"filteredProducts"列表，以仅显示与文本匹配的列表.

When the search text changes, you can dispatch an action to the store to update that string in the state i.e. store.dispatch(new ProductSkuEntered({ skuText: enteredText })); The NGXS selector will then automatically update your 'filteredProducts` list to display just those that match the text.

将debounceTime连接到文本更改中也很不错，以便仅在用户停止键入时才进行过滤.即仅在反跳后分派ProductSkuEntered.

It's also nice to hook up a debounceTime to the change in the text so that you only filter when the user has stopped typing. i.e. only dispatch the ProductSkuEntered after the debounce.

注意:我看到您正在使用NGXS表单插件-我没有使用该插件的经验，但是这种情况不是必需的(尽管您可能会在其他地方使用它).

Note: I see you are using the NGXS forms plugin - I don't have experience with that plugin but it is not required for this scenario (although you might be using it elsewhere).

这篇关于搜索/过滤状态NGXS的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！