---
id: 'plv8'
title: 'plv8: JavaScript Language'
description: 'JavaScript language for PostgreSQL.'
---

The `plv8` extension allows you use JavaScript within Postgres.

## Overview

While Postgres natively runs SQL, it can also run other procedural languages.
`plv8` allows you to run JavaScript code - specifically any code that runs on the [V8 JavaScript engine](https://v8.dev).

It can be used for database functions, triggers, queries and more.

## Enable the extension

<Tabs
  scrollable
  size="small"
  type="underlined"
  defaultActiveId="dashboard"
  queryGroup="database-method"
>
<TabPanel id="dashboard" label="Dashboard">

1. Go to the [Database](https://supabase.com/dashboard/project/_/database/tables) page in the Dashboard.
2. Click on **Extensions** in the sidebar.
3. Search for "plv8" and enable the extension.

</TabPanel>
<TabPanel id="sql" label="SQL">

```sql
-- Example: enable the "plv8" extension
create extension plv8;

-- Example: disable the "plv8" extension
drop extension if exists plv8;
```

Even though the SQL code is `create extension`, this is the equivalent of enabling the extension.
To disable an extension, call `drop extension`.

Procedural languages are automatically installed within `pg_catalog`, so you don't need to specify a schema.

</TabPanel>
</Tabs>

## Create `plv8` functions

Functions written in `plv8` are written just like any other PostgreSQL functions, only
with the `language` identifier set to `plv8`.

```sql
create or replace function function_name()
returns void as $$
    // V8 JavaScript
    // code
    // here
$$ language plv8;
```

You can call `plv8` functions like any other Postgres function:

<Tabs
  scrollable
  size="small"
  type="underlined"
  defaultActiveId="sql"
  queryGroup="language"
>
<TabPanel id="sql" label="SQL">

```sql
select function_name();
```

</TabPanel>
<TabPanel id="js" label="JavaScript">

```js
const { data, error } = supabase.rpc('function_name')
```

</TabPanel>
<TabPanel id="kotlin" label="Kotlin">

```kotlin
val data = supabase.postgrest.rpc("function_name")
```

</TabPanel>
</Tabs>

## Examples

### Scalar functions

A [scalar function](https://plv8.github.io/#scalar-function-calls) is anything that takes in some user input and returns a single result.

```sql
create or replace function hello_world(name text)
returns text as $$

    let output = `Hello, ${name}!`;
    return output;

$$ language plv8;
```

### Executing SQL

You can execute SQL within `plv8` code using the [`plv8.execute` function](https://plv8.github.io/#plv8-execute).

```sql
create or replace function update_user(id bigint, first_name text)
returns smallint as $$

    var num_affected = plv8.execute(
        'update profiles set first_name = $1 where id = $2',
        [first_name, id]
    );

    return num_affected;
$$ language plv8;
```

### Set-returning functions

A [set-returning function](https://plv8.github.io/#set-returning-function-calls) is anything that returns a full set of results - for example, rows in a table.

```sql
create or replace function get_messages()
returns setof messages as $$

    var json_result = plv8.execute(
        'select * from messages'
    );

    return json_result;
$$ language plv8;

select * from get_messages();
```

## Resources

- Official [`plv8` documentation](https://plv8.github.io/)
- [plv8 GitHub Repository](https://github.com/plv8/plv8)