feat: Export defineConfig defines the auxiliary function of the confi…

…guration (#4127)

* feat: Export defineConfig defines the auxiliary function of the configuration

* docs: Add some documentation for `defineConfig`

* docs: Set `Config Intellisense` as the fourth-level heading

Refer to: https://github.com/rollup/rollup/pull/4127/files/5d68a031143358ff84f6f91676af09061ed93a65

docs/01-command-line-reference.md

@@ -200,6 +200,33 @@ export default commandLineArgs => {
 }
 ```
 
+#### Config Intellisense
+
+Since Rollup ships with TypeScript typings, you can leverage your IDE's intellisense with jsdoc type hints:
+
+```javascript
+// rollup.config.js
+/**
+ * @type {import('rollup').RollupOptions}
+ */
+const config = {
+  // ...
+}
+
+export default config
+```
+
+Alternatively you can use the helper which should provide intellisense without the need for jsdoc annotations:defineConfig
+
+```javascript
+// rollup.config.js
+import { defineConfig } from 'rollup'
+
+export default defineConfig({
+  // ...
+})
+```
+
 ### Differences to the JavaScript API
 
 While config files provide an easy way to configure Rollup, they also limit how Rollup can be invoked and where configuration is taken from. Especially if you are rebundling Rollup in another build tool or want to integrate it into an advanced build process, it may be better to directly invoke Rollup programmatically from your scripts.

src/rollup/rollup.ts

@@ -20,6 +20,7 @@ import {
 	OutputOptions,
 	Plugin,
 	RollupBuild,
+	RollupOptions,
 	RollupOutput,
 	RollupWatcher
 } from './types';
@@ -282,3 +283,12 @@ function writeOutputFile(
 
 	return Promise.all([writeFile(fileName, source), writeSourceMapPromise]);
 }
+
+/**
+ * Auxiliary function for defining rollup configuration
+ * Mainly to facilitate IDE code prompts, after all, export default does not prompt, even if you add @type annotations, it is not accurate
+ * @param options
+ */
+export function defineConfig<T extends RollupOptions | RollupOptions[]>(options: T): T {
+	return options;
+}

src/rollup/types.d.ts

@@ -883,3 +883,6 @@ interface AcornNode {
 	start: number;
 	type: string;
 }
+
+export function defineConfig(options: RollupOptions): RollupOptions;
+export function defineConfig(options: RollupOptions[]): RollupOptions[];