# Install

Source: https://pgcast.dev/install

pgcast keeps Zapatos's module names, so you install it under the `zapatos` alias. Nothing in your imports changes.

## Requirements

- Postgres. The test suite runs against 14, 16 and 18.
- Node, and `pg` (node-postgres), with `@types/pg` for TypeScript.
- TypeScript 5.7 or later. `@types/pg` brings in `@types/node` and `pg-protocol`, whose types now need it; so does [`toBuffer()`](https://pgcast.dev/runtime-config#toBuffer)'s, `Buffer<ArrayBuffer>`, as in Zapatos 6.6.1.

### On an older TypeScript

pgcast's own types go back to TypeScript 4.1, the first with template literal types. Below 5.7, tell TypeScript not to check the types in `node_modules` (`toBuffer()` then returns `any`):

```json [tsconfig.json]
{
  "compilerOptions": {
    "skipLibCheck": true
  }
}
```

- From 5.0, that's all.
- Below 5.0, TypeScript can't read today's `@types/node`. Install the one made for your version, by its tag, and pin it: here for 4.1, `ts4.9` for 4.9.

```sh
npm install --save-dev --save-exact @types/node@ts4.1
```

> **Stale schema**
>
> `skipLibCheck` skips your generated `schema.d.ts` too. After an upgrade of pgcast, a schema you haven't regenerated no longer fails on `schemaVersionCanary` ([When the schema changes](https://pgcast.dev/first-query#when-the-schema-changes)): run `npx pgcast` each time.

## Add the package

```sh [npm]
npm install zapatos@npm:@pgcast/pgcast pg
npm install --save-dev @types/pg
```

```sh [pnpm]
pnpm add zapatos@npm:@pgcast/pgcast pg
pnpm add -D @types/pg
```

```sh [yarn]
yarn add zapatos@npm:@pgcast/pgcast@^6 pg
yarn add -D @types/pg
```

```sh [bun]
bun add zapatos@npm:@pgcast/pgcast@^6 pg
bun add -d @types/pg
```

Yarn 2 and later need a version range in an alias, and Yarn 1 and bun before 1.4 write none without one: hence the `@^6`.

> **Why the alias**
>
> The generated schema and the run-time code talk about `zapatos/db` and `zapatos/schema`. Installed as plain `@pgcast/pgcast`, those imports wouldn't resolve. Native `pgcast/*` names will come later, as an opt-in ([decision 002](https://github.com/AlexandreDemartin/pgcast/blob/master/docs/decisions/002-module-names.md)).

Already on Zapatos? Switching is one line of `package.json`, then a look for the few calls whose result changes: [Switch from Zapatos](https://pgcast.dev/switching).

That's pgcast in your project. Next, [First query](https://pgcast.dev/first-query) generates the types of a database, then runs a select and an insert with them.

Working with an assistant? It can read these docs from [llms.txt](https://pgcast.dev/llms.txt), an index of the pages, or [llms-full.txt](https://pgcast.dev/llms-full.txt), all of them in one file.