jarle/Bun Use Gel with Bun

Use Gel with Bun

Gel (formerly EdgeDB) is a graph-relational database powered by Postgres under the hood. It provides a declarative schema language, migrations system, and object-oriented query language, in addition to supporting raw SQL queries. It solves the object-relational mapping problem at the database layer, eliminating the need for an ORM library in your application code.

---

First, install Gel if you haven't already.

<CodeGroup> ```sh Linux/macOS terminal icon="terminal" theme={"theme":{"light":"github-light","dark":"dracula"}} curl https://www.geldata.com/sh --proto "=https" -sSf1 | sh ```

irm https://www.geldata.com/ps1 | iex

brew install geldata/tap/gel-cli

</CodeGroup>

---

Use bun init to create a fresh project.

mkdir my-edgedb-app
cd my-edgedb-app
bun init -y

---

We'll use the Gel CLI to initialize a Gel instance for our project. This creates a gel.toml file in our project root.

gel project init

No `gel.toml` found in `/Users/colinmcd94/Documents/bun/fun/examples/my-gel-app` or above
Do you want to initialize a new project? [Y/n]
> Y
Specify the name of Gel instance to use with this project [default: my_gel_app]:
> my_gel_app
Checking Gel versions...
Specify the version of Gel to use with this project [default: x.y]:
> x.y
┌─────────────────────┬──────────────────────────────────────────────────────────────────┐
│ Project directory   │ /Users/colinmcd94/Documents/bun/fun/examples/my-gel-app         │
│ Project config      │ /Users/colinmcd94/Documents/bun/fun/examples/my-gel-app/gel.toml│
│ Schema dir (empty)  │ /Users/colinmcd94/Documents/bun/fun/examples/my-gel-app/dbschema│
│ Installation method │ portable package                                                 │
│ Version             │ x.y+6d5921b                                                      │
│ Instance name       │ my_gel_app                                                       │
└─────────────────────┴──────────────────────────────────────────────────────────────────┘
Version x.y+6d5921b is already downloaded
Initializing Gel instance...
Applying migrations...
Everything is up to date. Revision initial
Project initialized.
To connect to my_gel_app, run `gel`

---

To see if the database is running, let's open a REPL and run a simple query.

gel
gel> select 1 + 1;

2

Then run \quit to exit the REPL.

gel> \quit

---

With the project initialized, we can define a schema. The gel project init command already created a dbschema/default.esdl file to contain our schema.

dbschema
├── default.esdl
└── migrations

---

Open that file and paste the following contents.

module default {
  type Movie {
    required title: str;
    releaseYear: int64;
  }
};

---

Then generate and apply an initial migration.

gel migration create

Created /Users/colinmcd94/Documents/bun/fun/examples/my-gel-app/dbschema/migrations/00001.edgeql, id: m1uwekrn4ni4qs7ul7hfar4xemm5kkxlpswolcoyqj3xdhweomwjrq

gel migrate

Applied m1uwekrn4ni4qs7ul7hfar4xemm5kkxlpswolcoyqj3xdhweomwjrq (00001.edgeql)

---

With our schema applied, let's execute some queries using Gel's JavaScript client library. We'll install the client library and Gel's codegen CLI, and create a seed.ts.file.

bun add gel
bun add -D @gel/generate
touch seed.ts

---

Paste the following code into seed.ts.

The client auto-connects to the database. We insert a couple movies using the .execute() method. We will use EdgeQL's for expression to turn this bulk insert into a single optimized query.

import { createClient } from "gel";

const client = createClient();

const INSERT_MOVIE = `
  with movies := <array<tuple<title: str, year: int64>>>$movies
  for movie in array_unpack(movies) union (
    insert Movie {
      title := movie.title,
      releaseYear := movie.year,
    }
  )
`;

const movies = [
  { title: "The Matrix", year: 1999 },
  { title: "The Matrix Reloaded", year: 2003 },
  { title: "The Matrix Revolutions", year: 2003 },
];

await client.execute(INSERT_MOVIE, { movies });

console.log(`Seeding complete.`);
process.exit();

---

Then run this file with Bun.

bun run seed.ts

Seeding complete.

---

Gel implements a number of code generation tools for TypeScript. To query our newly seeded database in a typesafe way, we'll use @gel/generate to code-generate the EdgeQL query builder.

bunx @gel/generate edgeql-js

Generating query builder...
Detected tsconfig.json, generating TypeScript files.
   To override this, use the --target flag.
   Run `npx @edgedb/generate --help` for full options.
Introspecting database schema...
Writing files to ./dbschema/edgeql-js
Generation complete! 🤘
Checking the generated query builder into version control
is not recommended. Would you like to update .gitignore to ignore
the query builder directory? The following line will be added:

   dbschema/edgeql-js

[y/n] (leave blank for "y")
> y

---

In index.ts, we can import the generated query builder from ./dbschema/edgeql-js and write a simple select query.

import { createClient } from "gel";
import e from "./dbschema/edgeql-js";

const client = createClient();

const query = e.select(e.Movie, () => ({
  title: true,
  releaseYear: true,
}));

const results = await query.run(client);
console.log(results);

results; // { title: string, releaseYear: number | null }[]

---

Running the file with Bun, we can see the list of movies we inserted.

bun run index.ts

[
  {
    title: "The Matrix",
    releaseYear: 1999
  }, {
    title: "The Matrix Reloaded",
    releaseYear: 2003
  }, {
    title: "The Matrix Revolutions",
    releaseYear: 2003
  }
]

---

For complete documentation, refer to the Gel docs.