feat(docs): add code gen page

docs/pages/repo/docs/core-concepts/monorepos/_meta.json

@@ -2,5 +2,6 @@
   "running-tasks": "Running Tasks",
   "task-dependencies": "Task Dependencies",
   "filtering": "Filtering Workspaces",
+  "code-generation": "Code Generation",
   "skipping-tasks": "Skipping Tasks in CI"
 }

docs/pages/repo/docs/core-concepts/monorepos/code-generation.mdx

@@ -0,0 +1,221 @@
+---
+title: Code Generation
+description: Extend your Turborepo with new apps, and packages. Create new empty workspaces, copy existing workspaces, add workspaces from remote sources (just like `create-turbo`!) or run custom generators defined using Plop configurations.
+---
+
+import Callout from "../../../../../components/Callout";
+
+# Code Generation
+
+Splitting your monorepo into individual workspaces is a great way to organize your code, speed up tasks, and improve the local development
+experience. One of the benefits of this approach is that it's easy to generate new source code for packages, modules,
+and even individual UI components. Turborepo generators makes extending your monorepo even easier.
+
+## Add an Empty Workspace
+
+Add a new, empty app or package to your monorepo.
+
+![Extend your Turborepo by adding a new package or application](/images/docs/turborepo-generators-empty.png)
+
+### Examples
+
+```sh
+turbo gen workspace
+```
+
+View all available [options](/repo/docs/reference/command-line-reference#workspace) for `gen workspace`.
+
+## Copy an Existing Workspace
+
+A new app or package can also be added using an existing workspace as a template. This works for both workspaces within your existing monorepo,
+and remote workspaces from other repositories (specified via github URL).
+
+![Extend your Turborepo by copying an existing package or application](/images/docs/turborepo-generators-copy.png)
+
+### Examples
+
+Extend your monorepo by copying from an existing workspace within your repo.
+
+```sh
+turbo gen workspace --copy
+```
+
+Extend your monorepo by copying from a remote workspace.
+
+```sh
+turbo gen workspace -e https://github.com/vercel/turbo/tree/main/examples/with-tailwind/packages/tailwind-config
+```
+
+<Callout>
+  **Note**: When adding from a remote source, Turborepo is unable to verify that your repo has all of the required dependencies, and is using the correct package manager. In this case, some manual modifications may be required to get the new workspace working as expected within your repository.
+
+</Callout>
+
+View all available [options](/repo/docs/reference/command-line-reference#workspace) for `gen workspace --copy`.
+
+## Custom Generators
+
+If a built-in generator does not fit your needs, you can create your own custom generator using [Plop](https://plopjs.com/) configurations.
+Turborepo will automatically detect any generator configurations within your repo, and make them available to run from the command line.
+
+While Turborepo understands all Plop configuration options and features, it provides a few additional features to improve the experience of writing
+generators within a repo configured with Turborepo.
+
+1. Generators are automatically discoverd, loaded, and organized per workspace (no need to manually `load` them within a single configuration file)
+2. Generators are automatically run from the root of the workspace where they are defined
+3. Generators can be invoked from anywhere within your repo (or outside out it via the [`--root`](/repo/docs/reference/command-line-reference#--root-1) flag)
+4. Typescript generators are supported with zero configuration
+5. `plop` is not required to be installed as a depenendency of your repo
+
+<Callout>
+  **Note:** ESM dependencies are not currently supported within custom generators
+</Callout>
+
+### Getting Started
+
+To build and run a custom generator, run the following command from anywhere within your monorepo using Turborepo.
+
+```sh
+turbo gen
+```
+
+You'll be prompted to select an existing generator or to create one if you don't have any yet. You can also create your configuration
+manually at `turbo/generators/config.ts` (or `config.js`) at the root of your repo - or within _any_ workspace.
+
+<Callout type="info">
+  **Note**: If you are using Typescript, you will need to install the [`@turbo/gen`](https://github.com/vercel/turbo/tree/main/packages/turbo-gen) package as a `devDependency` to access the required TS types.
+</Callout>
+
+For example, the following illustrates a monorepo with three generator configurations -
+
+```
+- root
+- apps/web
+- packages/ui
+```
+
+```bash
+├── package.json
+├── turbo.json
+├── README.md
+├── apps
+│   └── web
+│       ├── package.json
+│       └── turbo
+│           └── generators
+│               ├── config.ts
+│               └── templates
+├── packages
+│   └── ui
+│       ├── package.json
+│       └── turbo
+│           └── generators
+│               ├── config.ts
+│               └── templates
+├── turbo
+│   └── generators
+│       ├── config.ts
+│       └── templates
+├── pnpm-lock.yaml
+└── pnpm-workspace.yaml
+```
+
+Generators created within workspaces are automatically run from the workspace _root_, **not** the repo root, or the location of the generator config.
+
+This is done to make generators as simple to write as possible. Although the generator config is located within `[workspace-root]/turbo/generators`, creating a file at
+`[workspace-root]` does _not_ need to be specified as `../../<file>`, but rather simply `<file>`.
+
+Learn more about [creating custom generators using Plop](https://plopjs.com/documentation/#creating-a-generator).
+
+### Writing Generators
+
+A generator configuration file is a function that returns a [Plop](https://plopjs.com/) configuration object. The configuration object is
+used to define the generator's prompts, and actions.
+
+In its simplest form, a generator configuration file looks like:
+
+```ts filename="turbo/generators/config.ts"
+import type { PlopTypes } from "@turbo/gen";
+
+export default function generator(plop: PlopTypes.NodePlopAPI): void {
+  // create a generator
+  plop.setGenerator("Generator name", {
+    description: "Generator description",
+    // gather information from the user
+    prompts: [
+      ...
+    ],
+    // perform actions based on the prompts
+    actions: [
+      ...
+    ],
+  });
+}
+```
+
+#### Prompts
+
+Promps are written using [Plop prompts](https://plopjs.com/documentation/#using-prompts) and are used to gather information from the user.
+
+#### Actions
+
+Actions can use [built-in Plop actions](https://plopjs.com/documentation/#built-in-actions), or [custom action functions](https://plopjs.com/documentation/#functionsignature-custom-action) that you define yourself:
+
+```ts filename="turbo/generators/config.ts"
+import type { PlopTypes } from "@turbo/gen";
+
+const customAction: PlopTypes.CustomActionFunction = async (answers) => {
+  // fetch data from a remote API
+  const results = await fetchRemoteData();
+  // add the response to the answers, making this data available to actions
+  answers.results = results;
+  // return a status string
+  return 'Finished data fetching!';
+}
+
+export default function generator(plop: PlopTypes.NodePlopAPI): void {
+  // create a generator
+  plop.setGenerator("Generator name", {
+    description: "Generator description",
+    prompts: [
+      ...
+    ],
+    actions: [
+      customAction
+      {/* actions now have access to `answers.results` */}
+      ...
+    ],
+  });
+}
+```
+
+### Running Generators
+
+Once you have created your generator configuration file, you can skip the selection prompt and directly run a specified generator with:
+
+```sh
+turbo gen [generator-name]
+```
+
+<Callout type="info">
+  **Note**: While Turborepo Generators are built on top of Plop, they _do not_ require `plop` to be installed as a dependency in your repo.
+</Callout>
+
+Arguments can also be passed ditorectly to the generator prompts using `--args`
+
+```sh
+turbo gen [generator-name] --args answer1 answer2 ...
+```
+
+See [bypassing prompts](https://plopjs.com/documentation/#bypassing-prompts) for more information.
+
+View all available [options](/repo/docs/reference/command-line-reference#run-generator-name) for `gen`.
+
+## Examples
+
+The [vercel/turbo](https://github.com/vercel/turbo) monorepo contains several custom Turborepo generators that are used for our own development.
+
+- [Create a new blog post](https://github.com/vercel/turbo/blob/main/docs/turbo/generators/config.ts) - Creates a new release [blog post](/blog) with
+  live stats fetched from the NPM and Github API's.
+- [Create a new code transform](https://github.com/vercel/turbo/blob/main/packages/turbo-codemod/turbo/generators/config.ts) - Creates a new code transform
+  for [`@turbo/codemod`](https://github.com/vercel/turbo/tree/main/packages/turbo-codemod) complete with all boilerplate and tests.

docs/pages/repo/docs/reference/command-line-reference.mdx

@@ -706,5 +706,73 @@ Unlink the current directory from the Remote Cache.
 
 Get the path to the `turbo` binary.
 
+## `turbo gen`
+
+Extend your Turborepo with new apps, and packages. Create new empty workspaces, copy existing workspaces, add workspaces from remote sources or run custom generators defined using Plop configurations.
+
+**Note:** The default command for generate is [run](#run-generator-name).
+
+### `workspace`
+
+Add a new package or app to your monorepo.
+
+#### Options
+
+##### `--name`
+
+The name for the new workspace
+
+##### `--empty`
+
+Generate an empty workspace
+
+##### `--copy`
+
+Generate a workspace using an existing workspace as a template
+
+##### `--destination`
+
+Where the new workspace should be created
+
+##### `--type`
+
+The type of workspace to create ("app" or "package")
+
+##### `--root`
+
+The root of your repository (default: directory with _root_ turbo.json)
+
+##### `--example / -e`
+
+An example package to add. You can use a GitHub URL with any branch and/or subdirectory
+
+##### `--example-path`
+
+In a rare case, your GitHub URL might contain a branch name with a slash (e.g. bug/fix-1) and the path to the example (e.g. foo/bar).
+In this case, you must specify the path to
+the example separately: `--example-path foo/bar`
+
+##### `--show-all-dependencies`
+
+When selecting dependencies to add to your new workspace, do not filter available dependencies by the selected workspace type ("app" or "package")
+
+### `run [generator-name]`
+
+Run custom generators within your monorepo. Optionally specify a generator name to directly run a specific generator.
+
+#### Options
+
+##### `--config`
+
+Generator configuration file (default: turbo/generators/config.js)
+
+##### `--root`
+
+The root of your repository (default: directory with _root_ turbo.json)
+
+##### `--args`
+
+Prompt answers passed directly to generator
+
 [1]: /repo/docs/refernce/configuration#experimentalPassThroughEnv
 [2]: /repo/docs/refernce/configuration#experimentalGlobalPassThroughEnv