feat(modules): Allow adding generated public files (#769)

packages/wxt/e2e/tests/modules.test.ts

@@ -101,7 +101,13 @@ describe('Module Helpers', () => {
 
           export default defineWxtModule((wxt) => {
             addPublicAssets(wxt, "${normalizePath(dir)}")
-          })
+            wxt.hooks.hook("build:publicAssets", (_, assets) => {
+              assets.push({
+                relativeDest: "example/generated.txt",
+                contents: "",
+              });
+            });
+          });
         `,
       );
 
@@ -114,6 +120,9 @@ describe('Module Helpers', () => {
       await expect(
         project.fileExists('.output/chrome-mv3/module.txt'),
       ).resolves.toBe(true);
+      await expect(
+        project.fileExists('.output/chrome-mv3/example/generated.txt'),
+      ).resolves.toBe(true);
     });
 
     it("should not overwrite the user's public files", async () => {

packages/wxt/src/core/utils/building/build-entrypoints.ts

@@ -45,14 +45,18 @@ async function copyPublicDirectory(): Promise<BuildOutput['publicAssets']> {
   if (files.length === 0) return [];
 
   const publicAssets: BuildOutput['publicAssets'] = [];
-  for (const { absoluteSrc, relativeDest } of files) {
-    const absoluteDest = resolve(wxt.config.outDir, relativeDest);
+  for (const file of files) {
+    const absoluteDest = resolve(wxt.config.outDir, file.relativeDest);
 
     await fs.ensureDir(dirname(absoluteDest));
-    await fs.copyFile(absoluteSrc, absoluteDest);
+    if ('absoluteSrc' in file) {
+      await fs.copyFile(file.absoluteSrc, absoluteDest);
+    } else {
+      await fs.writeFile(absoluteDest, file.contents, 'utf8');
+    }
     publicAssets.push({
       type: 'asset',
-      fileName: relativeDest,
+      fileName: file.relativeDest,
     });
   }
 

packages/wxt/src/types/index.ts

@@ -1351,19 +1351,31 @@ export interface WxtModuleWithMetadata<TOptions extends WxtModuleOptions>
   id: string;
 }
 
-export interface ResolvedPublicFile {
+export type ResolvedPublicFile = CopiedPublicFile | GeneratedPublicFile;
+
+export interface ResolvedBasePublicFile {
+  /**
+   * The relative path in the output directory to copy the file to.
+   * @example
+   * "content-scripts/base-styles.css"
+   */
+  relativeDest: string;
+}
+
+export interface CopiedPublicFile extends ResolvedBasePublicFile {
   /**
    * The absolute path to the file that will be copied to the output directory.
    * @example
    * "/path/to/any/file.css"
    */
   absoluteSrc: string;
+}
+
+export interface GeneratedPublicFile extends ResolvedBasePublicFile {
   /**
-   * The relative path in the output directory to copy the file to.
-   * @example
-   * "content-scripts/base-styles.css"
+   * Text to write to the file.
    */
-  relativeDest: string;
+  contents: string;
 }
 
 export type WxtPlugin = () => void;