Angular2：如何应用过滤器* NG-的 [英] Angular2: how to apply filters to *ng-for

问题描述

显然Angular2将在拥堵上使用的管代替过滤器在Angular1与NG-的筛选结果，实现似乎仍然是模糊的，没有清晰的文档。

Apparently Angular2 will use pipe instead of filters as in Angular1 in congestion with ng-for to filter results, the implementation still seems to be vague, with no clear documentation..

即我想要实现可以从以下prespective被视为

Namely what I'm trying to achieve could be viewed from the following prespective

<div *ng-for="#item of itemsList" *ng-if="conditon(item)"></div>

如何实现如此使用管道？

How to implement so using pipes?

推荐答案

基本上，你写一个管道，然后您可以在使用 * NG-对指令。

Basically, you write a pipe which you can then use in the *ng-for directive.

在您的组件：

filterargs = {title: 'hello'};
items = [{title: 'hello world'}, {title: 'hello kitty'}, {title: 'foo bar'}];

在您的模板，你可以传递字符串，数字或对象的管道用来过滤的：

In your template, you can pass string, number or object to your pipe to use to filter on:

<li *ng-for="#item of items | myfilter:filterargs">

在您的管道：

@Pipe({
    name: 'myfilter',
    pure: false
})
@Injectable()
export class MyFilterPipe implements PipeTransform {
    transform(items: any[], args: any[]): any {
        // filter items array, items which match and return true will be kept, false will be filtered out
        return items.filter(item => item.title.indexOf(args[0].title) !== -1);
    }
}

诗。我跳过对象类型在本例中为简单起见，但你必须有ID，标题，日期等，你可以在使用的filterExpr对象应用于几项检查与函数的对象。

Ps. I skipped object typing in this example for simplicity, but you would have an object with id, title, date, etc which you could apply several checks on with a function using the filterargs object.

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