Angular pipes are a powerful feature that allows you to transform data directly in your HTML templates. With Angular 7, pipes have become even more versatile, enabling developers to manipulate data in various ways without altering the underlying data model. In this tutorial, we will explore the fundamentals of Angular 7 pipes and demonstrate their usage with practical examples.
Prerequisites
Before diving into Angular 7 pipes, make sure you have the following prerequisites installed:
- Node.js and npm
- Angular CLI
What are Pipes?
Pipes in Angular are simple functions that accept an input value and return a transformed value. They allow you to format data for display, filter and sort lists, and perform other data manipulation tasks directly in your templates. Angular provides several built-in pipes, and you can also create custom pipes to suit your specific requirements.
Built-in Pipes in Angular 7
Angular 7 comes with a set of built-in pipes that cover common data manipulation tasks. Some of the most commonly used built-in pipes include:
- DatePipe: Formats dates based on the locale.
- UpperCasePipe: Converts text to uppercase.
- LowerCasePipe: Converts text to lowercase.
- CurrencyPipe: Formats numbers as currency.
- DecimalPipe: Formats numbers as decimal numbers.
- PercentPipe: Formats numbers as percentages.
Using Built-in Pipes
Let’s look at some examples of how to use built-in pipes in Angular 7 templates:
<!-- DatePipe example -->
<p>Today is {{ today | date }}</p>
<!-- UpperCasePipe example -->
<p>{{ 'hello' | uppercase }}</p>
<!-- CurrencyPipe example -->
<p>Price: {{ price | currency:'USD':true }}</p>
Chaining Pipes
You can also chain multiple pipes together to perform complex transformations:
<p>{{ text | uppercase | slice:0:5 }}</p>
Creating Custom Pipes
In addition to built-in pipes, you can create custom pipes to meet your specific needs. Custom pipes are created using the @Pipe
decorator and implementing the PipeTransform
interface.
Here’s an example of a custom pipe that capitalizes the first letter of each word:
import { Pipe, PipeTransform } from '@angular/core';
@Pipe({ name: 'capitalize' })
export class CapitalizePipe implements PipeTransform {
transform(value: string): string {
return value.split(' ').map(word => word.charAt(0).toUpperCase() + word.slice(1)).join(' ');
}
}
To use this custom pipe in your templates, you would simply include it like any other built-in pipe:
<p>{{ 'hello world' | capitalize }}</p>
Conclusion
Angular 7 pipes are a powerful tool for transforming data directly in your templates. Whether you need to format dates, manipulate strings, or perform custom transformations, pipes provide a clean and efficient solution. By mastering Angular 7 pipes, you can enhance the readability and usability of your Angular applications. Start experimenting with pipes in your projects and unlock their full potential!