In this example, we have an array of objects called items. Each object contains a value and an id. Using trackBy, we pass a trackItems function which returns the id of each object. This id is used to provide a
To prevent that behavior, we can help angular with the identification of each object, by providing a so-called trackBy function. With this function, we can tell angular, which properties cause an object to be unique. In the case of our example, we can use the guid field to identify each...
for example when using the async pipe (userStreams | async).index: number: The index of the c...
EN使用带用户密码clone的方式： git clone https://username:password@remote 当username和password中含有...
CSS中的Viewport单元听起来很棒。如果你想将一个元素设置成全屏高度，你可以设置高度:100vh，这样你就有...
Lots of the Angular built-in pieces expect to be extended: consider router guards, http interceptors, form validators, etc. My example shows that you even extend ngFor to provide a new feature without it having to be in the core. Using this does not require the application developer to stop...
You can learn more about microsyntax in Angular's developer guide: http://bit.ly/ng6be-micro-syntax. This microsyntax exposes a number of iteration context properties that we can assign to template input variables and use them inside the ngFor HTML block. One such example is index. index...
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The use of TrackBy in my opinion is severely underrated in Angular. The performance benefits gained from using it can be huge (And very noticeable) for such a small code change. But before we dive too deep, let’s talk about how an NgFor loop works in Angular when you don’t use Trac...
Check out the live StackBlitz example:Free eBook Directives, simple right? Wrong! On the outside they look simple, but even skilled Angular devs haven’t grasped every concept in this eBook. Observables and Async Pipe Identity Checking and Performance Web Components <ng-template> syntax ...