19. Using Built-in Pipes (Date, Currency, Json)
Pipes are a way to transform data displayed in the template before it is rendered to the user. They are used in interpolation or other bindings using the pipe operator (|).
Syntax
html {{ expression | pipeName : argument1 : argument2 }}
Common Built-in Pipes
1. DatePipe
Formats a date value according to locale rules.
typescript currentDate: Date = new Date();
html
<p>Full Date: {{ currentDate | date }}</p> <!-- May 20, 2024 --> <p>Short Date: {{ currentDate | date:'shortDate' }}</p> <!-- 5/20/24 --> <p>Custom Format: {{ currentDate | date:'dd/MM/yyyy HH:mm' }}</p>2. CurrencyPipe
Formats a number as a currency string.
typescript productPrice: number = 129.50;
html
<!-- Default currency (USD) --> <p>Price: {{ productPrice | currency }}</p> <!-- $129.50 --> <!-- Custom currency (EUR), display code, custom format --> <p>EU Price: {{ productPrice | currency:'EUR':'symbol':'1.2-2' }}</p>3. JsonPipe
Useful for debugging. Converts a JavaScript value into a JSON string.
typescript userData = { id: 1, status: 'active' };
html
<!-- Displaying the entire object structure --> <pre>{{ userData | json }}</pre>4. Other Pipes
UppercasePipe,LowercasePipeSlicePipe(substring or array portion)DecimalPipe(number formatting)