API Reference / Angular InstantSearch Widgets / ais-hits-per-page
Apr. 24, 2019

ais-hits-per-page

You are reading the documentation for Angular InstantSearch v3, which is in beta. You can find the v2 documentation here.

Widget signature
<ais-hits-per-page
  [items]="object[]"
></ais-hits-per-page>

About this widget

The ais-hits-per-page widget displays a dropdown menu to let the user change the number of displayed hits.

If you only want to configure the number of hits per page without displaying a widget, you can use the ais-configure widget with the hitsPerPage search parameter.

Examples

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<ais-hits-per-page
  [items]="[
    { label: '8 hits per page', value: 8, default: true },
    { label: '16 hits per page', value: 16 },
  ]"
></ais-hits-per-page>

Props

items
type: object[]
Required

List of available options.

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<ais-hits-per-page
  [items]="[
    { label: '8 hits per page', value: 8, default: true },
    { label: '16 hits per page', value: 16 },
  ]"
></ais-hits-per-page>

Customize the UI - connectHitsPerPage

If you want to create your own UI of the ais-hits-per-page widget, you can combine the connectHitsPerPage connector with the BaseWidget class.

1. Extend the BaseWidget class

First of all, you will need to write some boilerplate code in order to initialize correctly the BaseWidget class. This happens in the constructor() of your class extending the BaseWidget class.

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import { Component, Inject, forwardRef } from '@angular/core';
import { BaseWidget, NgAisInstantSearch } from 'angular-instantsearch';

@Component({
  selector: 'app-hits-per-page',
  template: '<p>It works!</p>'
})
export class HitsPerPage extends BaseWidget {
  constructor(
    @Inject(forwardRef(() => NgAisInstantSearch))
    public instantSearchParent
  ) {
    super('HitsPerPage');
  }
}

There are a couple of things happening in this boilerplate:

  • we create a HitsPerPage class extending BaseWidget
  • we reference the <ais-instantsearch> parent component instance on the HitsPerPage widget class
  • we set app-hits-per-page as a selector, so we can use our component as <app-hits-per-page></app-hits-per-page>

2. Connect your custom widget

The BaseWidget class has a method called createWidget() which takes two arguments: the connector to use and an object of options (instance options) for this connector. We call this method at ngOnInit. This component now implements OnInit.

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import { Component, Inject, forwardRef } from '@angular/core';
import { BaseWidget, NgAisInstantSearch } from 'angular-instantsearch';
import { connectHitsPerPage } from 'instantsearch.js/es/connectors';

@Component({
  selector: 'app-hits-per-page',
  template: '<p>It works!</p>'
})
export class HitsPerPage extends BaseWidget {
  public state: {
    // render options
  };
  constructor(
    @Inject(forwardRef(() => NgAisInstantSearch))
    public instantSearchParent
  ) {
    super('HitsPerPage');
  }
  ngOnInit() {
    this.createWidget(connectHitsPerPage, {
      // instance options
      items: [
        {value: 6, label: '6 per page', default: true},
        {value: 12, label: '12 per page'},
        {value: 24, label: '24 per page'},
      ],
    });
    super.ngOnInit();
  }
}

3. Render from the state

Your component instance has access to a this.state property which holds the rendering options of the widget.

public state: {
  items: object[];
  hasNoResults: boolean;
  refine: Function;
  widgetParams: object;
}
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<select (change)="state.refine($event.target.value)">
  <option
    *ngFor="let item of state.items"
    [value]="item.value"
    [selected]="item.isRefined"
  >
    {{ item.label }}
  </option>
</select>

Rendering options

items
type: object[]

The list of items the widget can display, with each item:

  • label: string: the label to display in the option
  • value: number: the number of hits to display per page
  • isRefined: boolean: whether the item is the current refined value
hasNoResults
type: boolean

Whether or not the search has results.

refine
type: function

Sets the number of hits per page and triggers a search.

widgetParams
type: object

All original widget options forwarded to the render function.

Instance options

items
type: object[]
Required

The list of available options, with each item:

  • label: string: the label to display in the option
  • value: number: the number of hits to display per page
  • default: boolean: whether this is the default hits per page on first search.
transformItems
type: function
default: items => items
Optional

Receives the items, and is called before displaying them. Should return a new array with the same shape as the original array. Useful for mapping over the items to transform, and remove or reorder them.

Full example

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import { Component, Inject, forwardRef } from '@angular/core';
import { BaseWidget, NgAisInstantSearch } from 'angular-instantsearch';
import { connectHitsPerPage } from 'instantsearch.js/es/connectors';

@Component({
  selector: 'app-hits-per-page',
  template: `
<select (change)="state.refine($event.target.value)">
  <option
    *ngFor="let item of state.items"
    [value]="item.value"
    [selected]="item.isRefined"
  >
    {{ item.label }}
  </option>
</select>
`
})
export class HitsPerPage extends BaseWidget {
  public state: {
     items: object[];
     hasNoResults: boolean;
     refine: Function;
     widgetParams: object;
  };
  constructor(
    @Inject(forwardRef(() => NgAisInstantSearch))
    public instantSearchParent
  ) {
    super('HitsPerPage');
  }
  ngOnInit() {
    this.createWidget(connectHitsPerPage, {
      // instance options
      items: [
        {value: 6, label: '6 per page', default: true},
        {value: 12, label: '12 per page'},
        {value: 24, label: '24 per page'},
      ],
    });
    super.ngOnInit();
  }
}

HTML output

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<div class="ais-HitsPerPage">
  <select class="ais-HitsPerPage-select">
    <option class="ais-HitsPerPage-option" value="8">8 per page</option>
    <option class="ais-HitsPerPage-option" value="16">16 per page</option>
  </select>
</div>

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