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How Can I Apply A Quantity Limit To Ngfor Duplicate

When working with Angular applications, you may often find yourself needing to display a list of items using the `ngFor` directive. This powerful directive allows you to iterate over a collection and render elements dynamically. However, there are times when you want to apply a quantity limit to the elements displayed, especially when dealing with duplicates.

To achieve this in Angular, you can use a combination of `ngFor` and some simple TypeScript logic to control the number of duplicates displayed. Let's dive into how you can implement a quantity limit in your `ngFor` directive for duplicates.

First, you will need to create a custom pipe in Angular. Pipes are a handy feature that allows you to transform data in your templates. In this case, we will create a custom pipe to filter out duplicates based on a quantity limit.

Here's an example of how you can create a custom pipe for applying a quantity limit to `ngFor` duplicates:

Typescript

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'quantityLimit'
})
export class QuantityLimitPipe implements PipeTransform {
  transform(items: any[], limit: number): any[] {
    const uniqueItems = items.filter((item, index, self) =>
      index === self.findIndex((t) => (
        t.id === item.id
      ))
    );
    
    return uniqueItems.slice(0, limit);
  }
}

In the code above, we defined a `QuantityLimitPipe` that takes an array of items and a limit as input. The pipe then filters out duplicate items based on a unique key, in this case, the `id` field, and returns only the first `limit` number of unique items.

Next, you need to declare and use the custom pipe in your Angular component template where you are using `ngFor`. Here's how you can do it:

Html

<ul>
  <li>
    {{ item.name }}
  </li>
</ul>

In this example, we are limiting the display to three unique items based on the `name` field. You can adjust the limit value according to your requirements.

By implementing the custom pipe `quantityLimit` in your Angular application, you can easily apply a quantity limit to `ngFor` duplicates. This approach helps you control the number of duplicate items displayed and enhances the user experience by showing only a specified quantity.

In conclusion, managing duplicate items in an `ngFor` loop with a quantity limit is a common requirement in Angular applications. By creating a custom pipe to handle this scenario, you can efficiently display a controlled number of unique items. Experiment with the code snippets provided and adapt them to suit your specific needs in Angular development.

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