feat: lazy generate meta

Author: yjl9903

README.md

@@ -286,6 +286,19 @@ export default defineConfig({
 })
 ```
 
+You can also generate meta data lazily.
+
+```ts
+// vite.config.ts
+export default defineConfig({
+  plugins: [
+    BuildInfo({
+      meta: async () => ({ message: 'This is set from vite.config.ts' })
+    })
+  ]
+})
+```
+
 Then you can import them in your Vite app.
 
 ```ts

src/core/index.ts

@@ -97,7 +97,14 @@ export const UnpluginInfo = createUnplugin<Options | undefined>((option) => {
           `export const name = ${ci.name !== null ? `\`${ci.name}\`` : 'null'}`
         ].join('\n');
       } else if (id === ModuleName.BuildMeta) {
-        const body = Object.entries(option?.meta ?? {}).map(
+        const get = () => {
+          if (!option?.meta) return {};
+          if (typeof option.meta === 'function') {
+            return option.meta();
+          }
+          return option.meta;
+        };
+        const body = Object.entries(await get()).map(
           ([key, value]) => `export const ${key} = ${JSON.stringify(value, null, 2)};`
         );
         return body.join('\n');

src/core/types.ts

@@ -1,5 +1,7 @@
 import type { SimpleGit } from 'simple-git';
 
+type Metadata = Record<string | number, any>;
+
 export interface Options {
   /**
    * Git repo root path
@@ -26,7 +28,7 @@ export interface Options {
    *
    * Notice: meta data will be serialized to JSON format
    */
-  meta?: Record<string | number | symbol, any>;
+  meta?: Metadata | (() => Metadata | Promise<Metadata>);
 
   /**
    * Custom virtual module prefix