103 lines
2.5 KiB
Plaintext
103 lines
2.5 KiB
Plaintext
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p.location-badge.
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exported from <a href="/angular2/view.html">angular2/view</a>
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defined in <a href="https://github.com/angular/angular/tree/master/modules/angular2/src/core/compiler/query_list.js#L68">angular2/src/core/compiler/query_list.js (line 68)</a>
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:markdown
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An iterable live list of components in the Light DOM.
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Injectable Objects that contains a live list of child directives in the light DOM of a directive.
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The directives are kept in depth-first pre-order traversal of the DOM.
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The `QueryList` is iterable, therefore it can be used in both javascript code with `for..of` loop as well as in
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template with `*for="of"` directive.
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NOTE: In the future this class will implement an `Observable` interface. For now it uses a plain list of observable
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callbacks.
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# Example:
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Assume that `<tabs>` component would like to get a list its children which are `<pane>` components as shown in this
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example:
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```html
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<tabs>
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<pane title="Overview">...</pane>
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<pane *for="#o of objects" [title]="o.title">{{o.text}}</pane>
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</tabs>
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```
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In the above example the list of `<tabs>` elements needs to get a list of `<pane>` elements so that it could render
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tabs with the correct titles and in the correct order.
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A possible solution would be for a `<pane>` to inject `<tabs>` component and then register itself with `<tabs>`
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component's on `hydrate` and deregister on `dehydrate` event. While a reasonable approach, this would only work
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partialy since `*for` could rearange the list of `<pane>` components which would not be reported to `<tabs>`
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component and thus the list of `<pane>` componets would be out of sync with respect to the list of `<pane>` elements.
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A preferred solution is to inject a `QueryList` which is a live list of directives in the component`s light DOM.
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```javascript
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@Component({
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selector: 'tabs'
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})
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@View({
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template: `
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<ul>
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<li *for="#pane of panes">{{pane.title}}</li>
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</ul>
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<content></content>
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`
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})
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class Tabs {
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panes: QueryList<Pane>
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constructor(@Query(Pane) panes:QueryList<Pane>) {
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this.panes = panes;
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}
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}
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@Component({
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selector: 'pane',
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properties: ['title']
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})
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@View(...)
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class Pane {
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title:string;
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}
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```
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.l-main-section
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h2 Members
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.l-sub-section
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h3 onChange
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pre.prettyprint
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code.
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onChange(callback)
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:markdown
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.l-sub-section
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h3 removeCallback
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pre.prettyprint
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code.
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removeCallback(callback)
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:markdown
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