# Pipe

Pipes are simple functions that accept an input value and return a transformed value. They're easy to apply within template expressions, using the **pipe operator (**`|`**)**

```
<div>Title through uppercase pipe: {{title | uppercase}}</div>
```

* You can chain expressions through multiple pipes.

```
<div>
  Title through a pipe chain:
  {{title | uppercase | lowercase}}
</div>
```

* You can also [apply parameters](https://angular.io/guide/pipes#parameterizing-a-pipe) to a pipe

```
<div>Birthdate: {{currentHero?.birthdate | date:'longDate'}}</div>
```

## Angular Pipes

[Pipe API List ](https://angular.io/api?type=pipe)

Date

```markup
<!--output '2015-06-15 05:03 PM GMT+9'-->
<p>The custom date is {{today | date:'yyyy-MM-dd HH:mm a z':'+0900'}}</p>
```

## Self-define Pipes

A class with the `@Pipe` decorator defines a function that transforms input values to output values for display in a view.

\[R] <https://angular.io/guide/pipes>


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