feat(typescript): warn when compilerOptions.module is not esnext (#788)

* feat(typescript): warn when compilerOptions.module is not esnext

* fix: remove extra space

* test: update snapshots

* fix: add 2015 to list of valid ModuleKinds

package.json

@@ -31,6 +31,7 @@
  "codecov-lite": "^1.0.3",
  "del-cli": "^3.0.1",
  "eslint-config-rollup": "^1.0.0",
+ "esm": "^3.2.25",
  "execa": "^4.0.3",
  "globby": "^11.0.1",
  "husky": "^4.2.5",

packages/typescript/ava.config.js

@@ -0,0 +1 @@
+../../shared/ava.config.js

packages/typescript/package.json

@@ -62,23 +62,5 @@
  "rollup": "^2.14.0",
  "typescript": "^4.1.2"
  },
- "types": "types/index.d.ts",
- "ava": {
- "babel": {
- "compileEnhancements": false
- },
- "extensions": [
- "ts"
- ],
- "require": [
- "ts-node/register"
- ],
- "files": [
- "!**/fixtures/**",
- "!**/output/**",
- "!**/helpers/**",
- "!**/recipes/**",
- "!**/types.ts"
- ]
- }
+ "types": "types/index.d.ts"
 }

packages/typescript/src/index.ts

@@ -11,6 +11,7 @@ import getPluginOptions from './options/plugin';
 import { emitParsedOptionsErrors, parseTypescriptConfig } from './options/tsconfig';
 import { validatePaths, validateSourceMap } from './options/validate';
 import findTypescriptOutput, { getEmittedFile } from './outputFile';
+import { preflight } from './preflight';
 import createWatchProgram, { WatchProgramHelper } from './watchProgram';
 import TSCache from './tscache';
 
@@ -46,6 +47,8 @@ export default function typescript(options: RollupTypescriptOptions = {}): Plugi
  buildStart() {
  emitParsedOptionsErrors(ts, this, parsedOptions);
 
+ preflight(parsedOptions, this);
+
  // Fixes a memory leak https:/rollup/plugins/issues/322
  if (!program) {
  program = createWatchProgram(ts, this, {

packages/typescript/src/options/tsconfig.ts

@@ -2,7 +2,16 @@ import { readFileSync } from 'fs';
 import { dirname, resolve } from 'path';
 
 import { PluginContext } from 'rollup';
-import type { ExtendedConfigCacheEntry, ParsedCommandLine } from 'typescript';
+import type {
+ Diagnostic,
+ ExtendedConfigCacheEntry,
+ MapLike,
+ ParsedCommandLine,
+ ProjectReference,
+ TypeAcquisition,
+ WatchDirectoryFlags,
+ WatchOptions
+} from 'typescript';
 
 import { RollupTypescriptOptions } from '../../types';
 import diagnosticToWarning from '../diagnostics/toWarning';
@@ -16,6 +25,19 @@ import {
 } from './interfaces';
 import { normalizeCompilerOptions, makePathsAbsolute } from './normalize';
 
+export interface TypeScriptConfig {
+ autoSetSourceMap: boolean;
+ options: CompilerOptions;
+ typeAcquisition?: TypeAcquisition | undefined;
+ fileNames: string[];
+ projectReferences?: readonly ProjectReference[] | undefined;
+ watchOptions?: WatchOptions | undefined;
+ raw?: any;
+ errors: Diagnostic[];
+ wildcardDirectories?: MapLike<WatchDirectoryFlags> | undefined;
+ compileOnSave?: boolean | undefined;
+}
+
 /**
  * Finds the path to the tsconfig file relative to the current working directory.
  * @param relativePath Relative tsconfig path given by the user.
@@ -89,7 +111,7 @@ export function parseTypescriptConfig(
  ts: typeof import('typescript'),
  tsconfig: RollupTypescriptOptions['tsconfig'],
  compilerOptions: PartialCompilerOptions
-) {
+): TypeScriptConfig {
  /* eslint-disable no-undefined */
  const cwd = process.cwd();
  makePathsAbsolute(compilerOptions, cwd);

packages/typescript/src/preflight.ts

@@ -0,0 +1,19 @@
+import { PluginContext } from 'rollup';
+import { ModuleKind } from 'typescript';
+
+import { TypeScriptConfig } from './options/tsconfig';
+
+const moduleError = `
+Rollup requires that TypeScript produces ES Modules. Unfortunately your configuration specifies a
+ "module" other than "esnext". Unless you know what you're doing, please change "module" to "esnext"
+ in the target tsconfig.json file or plugin options.`.replace(/\n/g, '');
+
+let undef;
+const validModules = [ModuleKind.ES2015, ModuleKind.ES2020, ModuleKind.ESNext, undef];
+
+// eslint-disable-next-line import/prefer-default-export
+export const preflight = (config: TypeScriptConfig, context: PluginContext) => {
+ if (!validModules.includes(config.options.module)) {
+ context.warn(`@rollup/plugin-typescript: ${moduleError}`);
+ }
+};

packages/typescript/test/fixtures/bad-module/main.ts

@@ -0,0 +1,3 @@
+const answer = 42;
+// eslint-disable-next-line no-console
+console.log(`the answer is ${answer}`);

packages/typescript/test/fixtures/bad-module/tsconfig.json

@@ -0,0 +1,5 @@
+{
+ "compilerOptions": {
+ "module": "commonjs"
+ }
+}

packages/typescript/test/snapshots/warnings.ts.md

@@ -0,0 +1,18 @@
+# Snapshot report for `test/warnings.ts`
+
+The actual snapshot is saved in `warnings.ts.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## bad module in tsconfig
+
+> Snapshot 1
+
+ [
+  {
+  code: 'PLUGIN_WARNING',
+  message: '@rollup/plugin-typescript: Rollup requires that TypeScript produces ES Modules. Unfortunately your configuration specifies a "module" other than "esnext". Unless you know what you\'re doing, please change "module" to "esnext" in the target tsconfig.json file or plugin options.',
+  plugin: 'typescript',
+  toString: Function {},
+  },
+ ]

packages/typescript/test/warnings.ts

@@ -0,0 +1,17 @@
+import test from 'ava';
+import { rollup } from 'rollup';
+
+import typescript from '..';
+
+test.beforeEach(() => process.chdir(__dirname));
+
+test.serial('bad module in tsconfig', async (t) => {
+ const warnings: any[] = [];
+ await rollup({
+ input: 'fixtures/bad-module/main.ts',
+ plugins: [typescript({ tsconfig: 'fixtures/bad-module/tsconfig.json' })],
+ onwarn: (warning) => warnings.push(warning)
+ });
+
+ t.snapshot(warnings);
+});

shared/ava.config.js

@@ -0,0 +1,5 @@
+export default {
+ extensions: ['js', 'ts'],
+ files: ['!**/fixtures/**', '!**/output/**', '!**/helpers/**', '!**/recipes/**', '!**/types.ts'],
+ require: ['ts-node/register', 'esm']
+};

tsconfig.base.json

@@ -1,6 +1,7 @@
 {
  "compilerOptions": {
  "allowSyntheticDefaultImports": true,
+ "esModuleInterop": true,
  "lib": ["es6"],
  "module": "esnext",
  "moduleResolution": "node",

tsconfig.eslint.json

@@ -1,4 +1,4 @@
 {
  "extends": "./tsconfig.base.json",
- "include": ["packages", "scripts", "util"]
+ "include": ["packages", "scripts", "shared", "util"]
 }