---
title: Hooks Examples
label: Examples
order: 20
---

### Collection Hooks

#### Set createdBy and lastModifiedBy

```js
beforeChange: [
  ({ req, operation }) => {
    if (req.user && req.body) {
      if (operation === 'create') {
        req.body.createdBy = req.user.id;
      }
      req.body.lastModifiedBy = req.user.id;
    }
  }
]
```
_NOTE: createdBy and lastModifiedBy must be fields on the collection_

#### Use Local Payload API

Queries a separate collection and appends to returned result

```js
afterRead: [
  async ({ req, doc }) => {
    const formattedData = { ...doc };
    const posts = await req.payload.find({
      collection: 'posts',
    });

    formattedData.posts = posts;

    return formattedData;
  },
],
```

#### Read Request Header

```js
beforeRead: [
  ({ req }) => {
    if (req.headers.specialheader === 'special') {
      // Do something...
    }
  },
],
```

### Field Hooks

#### Kebab-case Formatter

```js
beforeValidate: [
  ({ value }) => val.replace(/ /g, '-').toLowerCase();
]
```