## `bun init`

Scaffold an empty project with the interactive `bun init` command.

```bash
$ bun init
bun init helps you get started with a minimal project and tries to
guess sensible defaults. Press ^C anytime to quit.

package name (quickstart):
entry point (index.ts):

Done! A package.json file was saved in the current directory.
 + index.ts
 + .gitignore
 + tsconfig.json (for editor auto-complete)
 + README.md

To get started, run:
  bun run index.ts
```

Press `enter` to accept the default answer for each prompt, or pass the `-y` flag to auto-accept the defaults.

## `bun create`

Template a new Bun project with `bun create`.

```bash
$ bun create <template> <destination>
```

{% callout %}
**Note** — You don’t need `bun create` to use Bun. You don’t need any configuration at all. This command exists to make getting started a bit quicker and easier.
{% /callout %}

A template can take a number of forms:

```bash
$ bun create <template>         # an official template (remote)
$ bun create <username>/<repo>  # a GitHub repo (remote)
$ bun create <local-template>   # a custom template (local)
```

Running `bun create` performs the following steps:

- Download the template (remote templates only)
- Copy all template files into the destination folder. By default Bun will _not overwrite_ any existing files. Use the `--force` flag to overwrite existing files.
- Install dependencies with `bun install`.
- Initialize a fresh Git repo. Opt out with the `--no-git` flag.
- Run the template's configured `start` script, if defined.

### Official templates

The following official templates are available.

```bash
bun create next ./myapp
bun create react ./myapp
bun create svelte-kit ./myapp
bun create elysia ./myapp
bun create hono ./myapp
bun create kingworld ./myapp
```

Each of these corresponds to a directory in the [bun-community/create-templates](https://github.com/bun-community/create-templates) repo. If you think a major framework is missing, please open a PR there. This list will change over time as additional examples are added. To see an up-to-date list, run `bun create` with no arguments.

```bash
$ bun create
Welcome to bun! Create a new project by pasting any of the following:
  <list of templates>
```

{% callout %}
⚡️ **Speed** — At the time of writing, `bun create react app` runs ~11x faster on a M1 Macbook Pro than `yarn create react-app app`.
{% /callout %}

### GitHub repos

A template of the form `<username>/<repo>` will be downloaded from GitHub.

```bash
$ bun create ahfarmer/calculator ./myapp
```

Complete GitHub URLs will also work:

```bash
$ bun create github.com/ahfarmer/calculator ./myapp
$ bun create https://github.com/ahfarmer/calculator ./myapp
```

Bun installs the files as they currently exist current default branch (usually `main` or `master`). Unlike `git clone` it doesn't download the commit history or configure a remote.

### Local templates

{% callout %}
**⚠️ Warning** — Unlike remote templates, running `bun create` with a local template will delete the entire destination folder if it already exists! Be careful.
{% /callout %}
Bun's templater can be extended to support custom templates defined on your local file system. These templates should live in one of the following directories:

- `$HOME/.bun-create/<name>`: global templates
- `<project root>/.bun-create/<name>`: project-specific templates

{% callout %}
**Note** — You can customize the global template path by setting the `BUN_CREATE_DIR` environment variable.
{% /callout %}

To create a local template, navigate to `$HOME/.bun-create` and create a new directory with the desired name of your template.

```bash
$ cd $HOME/.bun-create
$ mkdir foo
$ cd foo
```

Then, create a `package.json` file in that directory with the following contents:

```json
{
  "name": "foo"
}
```

You can run `bun create foo` elsewhere on your file system to verify that Bun is correctly finding your local template.

{% table %}

---

- `postinstall`
- runs after installing dependencies

---

- `preinstall`
- runs before installing dependencies

<!-- ---

- `start`
- a command to auto-start the application -->

{% /table %}

Each of these can correspond to a string or array of strings. An array of commands will be executed in order. Here is an example:

```json
{
  "name": "@bun-examples/simplereact",
  "version": "0.0.1",
  "main": "index.js",
  "dependencies": {
    "react": "^17.0.2",
    "react-dom": "^17.0.2"
  },
  "bun-create": {
    "preinstall": "echo 'Installing...'", // a single command
    "postinstall": ["echo 'Done!'"], // an array of commands
    "start": "bun run echo 'Hello world!'"
  }
}
```

When cloning a template, `bun create` will automatically remove the `"bun-create"` section from `package.json` before writing it to the destination folder.

### Reference

#### CLI flags

{% table %}

- Flag
- Description

---

- `--force`
- Overwrite existing files

---

- `--no-install`
- Skip installing `node_modules` & tasks

---

- `--no-git`
- Don’t initialize a git repository

---

- `--open`
- Start & open in-browser after finish

{% /table %}

#### Environment variables

{% table %}

- Name
- Description

---

- `GITHUB_API_DOMAIN`
- If you’re using a GitHub enterprise or a proxy, you can customize the GitHub domain Bun pings for downloads

---

- `GITHUB_API_TOKEN`
- This lets `bun create` work with private repositories or if you get rate-limited

{% /table %}

{% details summary="How `bun create` works" %}

When you run `bun create ${template} ${destination}`, here’s what happens:

IF remote template

1. GET `registry.npmjs.org/@bun-examples/${template}/latest` and parse it
2. GET `registry.npmjs.org/@bun-examples/${template}/-/${template}-${latestVersion}.tgz`
3. Decompress & extract `${template}-${latestVersion}.tgz` into `${destination}`

   - If there are files that would overwrite, warn and exit unless `--force` is passed

IF GitHub repo

1. Download the tarball from GitHub’s API
2. Decompress & extract into `${destination}`

   - If there are files that would overwrite, warn and exit unless `--force` is passed

ELSE IF local template

1. Open local template folder
2. Delete destination directory recursively
3. Copy files recursively using the fastest system calls available (on macOS `fcopyfile` and Linux, `copy_file_range`). Do not copy or traverse into `node_modules` folder if exists (this alone makes it faster than `cp`)

4. Parse the `package.json` (again!), update `name` to be `${basename(destination)}`, remove the `bun-create` section from the `package.json` and save the updated `package.json` to disk.
   - IF Next.js is detected, add `bun-framework-next` to the list of dependencies
   - IF Create React App is detected, add the entry point in /src/index.{js,jsx,ts,tsx} to `public/index.html`
   - IF Relay is detected, add `bun-macro-relay` so that Relay works
5. Auto-detect the npm client, preferring `pnpm`, `yarn` (v1), and lastly `npm`
6. Run any tasks defined in `"bun-create": { "preinstall" }` with the npm client
7. Run `${npmClient} install` unless `--no-install` is passed OR no dependencies are in package.json
8. Run any tasks defined in `"bun-create": { "preinstall" }` with the npm client
9. Run `git init; git add -A .; git commit -am "Initial Commit";`

   - Rename `gitignore` to `.gitignore`. NPM automatically removes `.gitignore` files from appearing in packages.
   - If there are dependencies, this runs in a separate thread concurrently while node_modules are being installed
   - Using libgit2 if available was tested and performed 3x slower in microbenchmarks

{% /details %}