> ## Documentation Index
> Fetch the complete documentation index at: https://cockroachlabs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Userscript Quickstart
export const InternalLink = ({version, path = "", children, ...props}) => {
let detectedVersion = version || "stable";
if (typeof window !== 'undefined' && !version) {
const match = window.location.pathname.match(/\/docs\/([^/]+)/);
if (match) {
detectedVersion = match[1];
}
}
const normalizedPath = path.startsWith("/") ? path.slice(1) : path;
return
{children}
;
};
This quickstart guides you through creating, validating, and deploying your first userscript based on a cookbook example.
## Before you begin
* Install MOLT Replicator **v1.3.0 or later** for full compatibility with the userscript API.
* Install a TypeScript-compatible IDE (for example, [VS Code](https://code.visualstudio.com/)).
## Step 1: Set up your environment
Create a new TypeScript file for your userscript in your IDE (for example, `userscript.ts`).
For IDE autocomplete and type-checking support, optionally add the Replicator TypeScript definitions. For details, refer to Access this API.
## Step 2: Write a userscript
Use the userscript cookbook as a starting point. The cookbook provides ready-to-use examples that you can copy and adapt.
Copy and adapt a cookbook example that matches your use case. For example, adapt the template to filter a single table to exclude the `audit_logs` table from the `public` schema during replication:
```ts theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
import * as api from "replicator@v2";
const TARGET_SCHEMA_NAME = "defaultdb.public";
const TABLE_TO_SKIP = "audit_logs";
api.configureTargetSchema(TARGET_SCHEMA_NAME, {
onRowUpsert: (row, meta) => {
if (meta.table === TABLE_TO_SKIP) {
return null; // Skip this table
}
return row;
},
onRowDelete: (row, meta) => {
if (meta.table === TABLE_TO_SKIP) {
return null;
}
return row;
}
});
```
For details on the userscript API and handler functions, refer to the Userscript API.
When writing userscripts, follow the best practices.
## Step 3: Use with Replicator
Include the `--userscript` flag to have MOLT Replicator apply the userscript. For example, to apply your userscript during PostgreSQL replication:
```shell theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
replicator pglogical \
--sourceConn $SOURCE \
--targetConn $TARGET \
--targetSchema defaultdb.public \
--slotName molt_slot \
--publicationName molt_fetch \
--stagingSchema defaultdb._replicator \
--stagingCreateSchema \
--userscript userscript.ts
```
## See also
* Userscript Overview
* Userscript API
* Userscript Cookbook
* MOLT Replicator