feat(transformer): explain about runtime helpers

.vitepress/config/en.ts

@@ -224,6 +224,10 @@ export const enConfig = defineLocaleConfig("root", {
               text: "Isolated Declarations",
               link: "/docs/guide/usage/transformer/isolated-declarations",
             },
+            {
+              text: "Runtime Helpers",
+              link: "/docs/guide/usage/transformer/runtime-helpers",
+            },
           ],
         },
         {

src/docs/guide/usage/transformer.md

@@ -22,6 +22,10 @@ Use the umbrella crate [oxc][url-oxc-crate] with the `transformer` feature.
 
 Rust usage example can be found [here](https://github.com/oxc-project/oxc/blob/main/crates/oxc_transformer/examples/transformer.rs).
 
+## Runtime Helpers
+
+The transformer may inject imports from [`@oxc-project/runtime`](./transformer/runtime-helpers), a package containing Oxc's runtime helpers. See the [runtime helpers guide](./transformer/runtime-helpers) for how to handle this.
+
 ## Integrations
 
 - [`unplugin-oxc`](https://npmx.dev/package/unplugin-oxc)

src/docs/guide/usage/transformer/runtime-helpers.md

@@ -0,0 +1,41 @@
+# Runtime Helpers
+
+The transformer may inject import statements from `@oxc-project/runtime`, a package containing Oxc's runtime helpers. There are two ways to handle this.
+
+## Bundling the Helpers
+
+If you are using a bundler, the runtime helpers will be resolved and bundled into your output. This is the only option for non-Node apps. For Node apps and libraries, this is also suitable when you don't want to manage the runtime version yourself.
+
+No additional setup is required — your bundler will handle the imports automatically.
+
+## Externalizing the Helpers
+
+Alternatively, you can add `@oxc-project/runtime` to your dependencies and externalize the imports. You need to select the runtime version that matches your `oxc-transform` version (see [version compatibility](#version-compatibility) below).
+
+The benefit of this approach is deduplication: when a user depends on multiple libraries that were transformed with Oxc, the runtime helpers are shared rather than duplicated in each bundle.
+
+::: code-group
+
+```sh [npm]
+npm add @oxc-project/runtime
+```
+
+```sh [pnpm]
+pnpm add @oxc-project/runtime
+```
+
+```sh [yarn]
+yarn add @oxc-project/runtime
+```
+
+```sh [bun]
+bun add @oxc-project/runtime
+```
+
+:::
+
+## Version Compatibility
+
+| `oxc-transform` | `@oxc-project/runtime` |
+| --------------- | ---------------------- |
+| 0.115.0         | 0.115.0                |