Add rollup declarations plugin

This invokes glint as a rollup plugin, and contains a workaround for broken gts imports, see typed-ember/glint#628

packages/addon-dev/jest.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  testEnvironment: 'node',
+  testMatch: [
+    '<rootDir>/tests/**/*.test.js',
+  ],
+};

packages/addon-dev/package.json

@@ -37,6 +37,7 @@
     "@embroider/core": "workspace:^",
     "@rollup/pluginutils": "^4.1.1",
     "content-tag": "^3.0.0",
+    "execa": "^5.1.1",
     "fs-extra": "^10.0.0",
     "minimatch": "^3.0.4",
     "rollup-plugin-copy-assets": "^2.0.3",
@@ -46,11 +47,15 @@
   "devDependencies": {
     "@embroider/test-support": "workspace:*",
     "@glimmer/syntax": "^0.84.2",
+    "@glint/core": "^1.5.0",
+    "@glint/template": "^1.5.0",
+    "@glint/environment-ember-loose": "^1.5.0",
+    "@glint/environment-ember-template-imports": "^1.5.0",
     "@types/fs-extra": "^9.0.12",
     "@types/minimatch": "^3.0.4",
     "@types/yargs": "^17.0.3",
     "rollup": "^3.23.0",
-    "tmp": "^0.1.0",
+    "scenario-tester": "^4.0.0",
     "typescript": "^5.4.5"
   },
   "engines": {

packages/addon-dev/src/rollup-declarations.ts

@@ -0,0 +1,50 @@
+import execa from 'execa';
+import walkSync from 'walk-sync';
+import { readFile, writeFile } from 'fs/promises';
+
+export default function rollupDeclarationsPlugin(declarationsDir: string) {
+  let glintPromise: Promise<void>;
+
+  return {
+    name: 'glint-dts',
+    buildStart: () => {
+      const runGlint = async () => {
+        await execa('glint', ['--declaration'], {
+          stdio: 'inherit',
+          preferLocal: true,
+        });
+
+        await fixDeclarationsInMatchingFiles(declarationsDir);
+      };
+
+      // We just kick off glint here early in the rollup process, without making rollup wait for this to finish, by not returning the promise
+      // The output of this is not relevant to further stages of the rollup build, this is just happening in parallel to other rollup compilation
+      glintPromise = runGlint();
+    },
+
+    // Make rollup wait for glint to have finished before calling the build job done
+    writeBundle: () => glintPromise,
+  };
+}
+
+async function fixDeclarationsInMatchingFiles(dir: string) {
+  const dtsFiles = walkSync(dir, {
+    globs: ['**/*.d.ts'],
+    directories: false,
+    includeBasePath: true,
+  });
+
+  return Promise.all(
+    dtsFiles.map(async (file) => {
+      const content = await readFile(file, { encoding: 'utf8' });
+
+      await writeFile(file, fixDeclarations(content));
+    })
+  );
+}
+
+// Strip any .gts extension from imports in d.ts files, as these won't resolve. See https://github.com/typed-ember/glint/issues/628
+// Once Glint v2 is available, this shouldn't be needed anymore.
+function fixDeclarations(content: string) {
+  return content.replaceAll(/from\s+['"]([^'"]+)\.gts['"]/g, `from '$1'`);
+}

packages/addon-dev/src/rollup.ts

@@ -3,6 +3,7 @@ import { default as gjs } from './rollup-gjs-plugin';
 import { default as publicEntrypoints } from './rollup-public-entrypoints';
 import { default as appReexports } from './rollup-app-reexports';
 import { default as keepAssets } from './rollup-keep-assets';
+import { default as declarations } from './rollup-declarations';
 import { default as dependencies } from './rollup-addon-dependencies';
 import {
   default as publicAssets,
@@ -108,4 +109,8 @@ export class Addon {
   publicAssets(path: string, opts?: PublicAssetsOptions) {
     return publicAssets(path, opts);
   }
+
+  declarations(path: string) {
+    return declarations(path);
+  }
 }

packages/addon-dev/tests/declarations.test.ts

@@ -0,0 +1,109 @@
+'use strict';
+
+import rollupDeclarationsPlugin from '../src/rollup-declarations';
+import { Project } from 'scenario-tester';
+import { rollup } from 'rollup';
+import { readFile } from 'fs-extra';
+import { join } from 'path';
+
+const projectBoilerplate = {
+  'tsconfig.json': JSON.stringify({
+    include: ['src/**/*'],
+    compilerOptions: {
+      declaration: true,
+      declarationDir: 'declarations',
+      emitDeclarationOnly: true,
+      rootDir: './src',
+      allowImportingTsExtensions: true,
+    },
+    glint: {
+      environment: ['ember-loose', 'ember-template-imports'],
+    },
+  }),
+};
+
+async function generateProject(src: {}): Promise<Project> {
+  const project = new Project('my-addon', {
+    files: {
+      ...projectBoilerplate,
+      src,
+    },
+  });
+  project.linkDevDependency('typescript', { baseDir: __dirname });
+  project.linkDevDependency('@glint/core', { baseDir: __dirname });
+  project.linkDevDependency('@glint/template', { baseDir: __dirname });
+  project.linkDevDependency('@glint/environment-ember-loose', {
+    baseDir: __dirname,
+  });
+  project.linkDevDependency('@glint/environment-ember-template-imports', {
+    baseDir: __dirname,
+  });
+
+  await project.write();
+
+  return project;
+}
+
+async function runRollup(dir: string, rollupOptions = {}) {
+  const currentDir = process.cwd();
+  process.chdir(dir);
+
+  try {
+    const bundle = await rollup({
+      input: './src/index.ts',
+      plugins: [rollupDeclarationsPlugin('declarations')],
+      ...rollupOptions,
+    });
+
+    await bundle.write({ format: 'esm', dir: 'dist' });
+  } finally {
+    process.chdir(currentDir);
+  }
+}
+
+describe('declarations', function () {
+  let project: Project | null;
+
+  afterEach(() => {
+    project?.dispose();
+    project = null;
+  });
+
+  test('it generates dts output', async function () {
+    project = await generateProject({
+      'index.ts': 'export default 123',
+    });
+
+    await runRollup(project.baseDir);
+
+    expect(
+      await readFile(join(project.baseDir, 'declarations/index.d.ts'), {
+        encoding: 'utf8',
+      })
+    ).toContain('export default');
+  });
+
+  test('it has correct imports', async function () {
+    project = await generateProject({
+      'index.ts': `
+        import foo from './foo.gts';
+        import bar from './bar.ts';
+        export { foo, bar };
+      `,
+      'foo.gts': 'export default 123',
+      'bar.ts': 'export default 234',
+    });
+
+    await runRollup(project.baseDir);
+
+    const output = await readFile(
+      join(project.baseDir, 'declarations/index.d.ts'),
+      {
+        encoding: 'utf8',
+      }
+    );
+
+    expect(output).toContain(`import foo from './foo';`);
+    expect(output).toContain(`import bar from './bar.ts';`);
+  });
+});

tsconfig.json

@@ -7,7 +7,7 @@
     "./tests/scenarios/**/*.ts"
   ],
   "compilerOptions": {
-    "target": "es2019",
+    "target": "es2021",
     "module": "commonjs",
     "declaration": true,
     "typeRoots": ["types", "node_modules/@types"],