new: Polyfill node modules for other platforms. (#26)

* Add dep.

* Start outputs.

* Remove sourcemaps.

* Test polyfills.

* Test generators.

* Test async/await.

package.json

@@ -101,6 +101,7 @@
     "rimraf": "^3.0.2",
     "rollup": "^2.38.5",
     "rollup-plugin-node-externals": "^2.2.0",
+    "rollup-plugin-polyfill-node": "^0.5.0",
     "rollup-plugin-visualizer": "^4.2.0",
     "semver": "^7.3.4",
     "spdx-license-list": "^6.4.0",

src/babel/config.ts

@@ -145,7 +145,6 @@ export function getBabelOutputConfig(
 ): ConfigStructure {
   const plugins: PluginItem[] = [];
   const presets: PluginItem[] = [];
-  const isFuture = support !== 'legacy' && support !== 'stable';
 
   // ENVIRONMENT
 
@@ -168,27 +167,25 @@ export function getBabelOutputConfig(
 
   // Use `Object.assign` when available
   // https://babeljs.io/docs/en/babel-plugin-transform-destructuring#usebuiltins
-  if (isFuture) {
+  if (support === 'current' || support === 'experimental') {
     plugins.push(
       [resolve('@babel/plugin-transform-destructuring'), { useBuiltIns: true }],
       [resolve('@babel/plugin-proposal-object-rest-spread'), { useBuiltIns: true }],
     );
   }
 
-  if (platform === 'browser' || platform === 'native') {
+  if ((platform === 'browser' || platform === 'native') && support !== 'experimental') {
     // Transform async/await into Promises
     plugins.push([
       resolve('babel-plugin-transform-async-to-promises'),
-      { inlineHelpers: true, target: isFuture ? 'es6' : 'es5' },
+      { inlineHelpers: true, target: 'es5' },
     ]);
 
-    // Transform generators for legacy
-    if (!isFuture) {
-      plugins.push([
-        resolve('@babel/plugin-transform-runtime'),
-        { helpers: false, regenerator: true, useESModules: format === 'esm' },
-      ]);
-    }
+    // Transform generators to Regenerator
+    plugins.push([
+      resolve('@babel/plugin-transform-runtime'),
+      { helpers: false, regenerator: true, useESModules: format === 'esm' },
+    ]);
   }
 
   // Support env expression shortcuts

src/rollup/config.ts

@@ -1,6 +1,7 @@
 import path from 'path';
 import { ModuleFormat, OutputOptions, RollupOptions } from 'rollup';
 import externals from 'rollup-plugin-node-externals';
+import nodePolyfills from 'rollup-plugin-polyfill-node';
 import visualizer from 'rollup-plugin-visualizer';
 import { getBabelInputPlugin, getBabelOutputPlugin } from '@rollup/plugin-babel';
 import commonjs from '@rollup/plugin-commonjs';
@@ -138,6 +139,7 @@ export function getRollupOutputConfig(
 export function getRollupConfig(artifact: BundleArtifact, features: FeatureFlags): RollupOptions {
   const inputPath = artifact.getInputPath();
   const packagePath = path.resolve(artifact.package.packageJsonPath.path());
+  const isNode = artifact.platform === 'node';
 
   const config: RollupOptions = {
     cache: artifact.cache,
@@ -148,7 +150,7 @@ export function getRollupConfig(artifact: BundleArtifact, features: FeatureFlags
     plugins: [
       // Mark all dependencies in `package.json` as external
       externals({
-        builtins: true,
+        builtins: isNode,
         deps: true,
         devDeps: true,
         optDeps: true,
@@ -172,6 +174,12 @@ export function getRollupConfig(artifact: BundleArtifact, features: FeatureFlags
     treeshake: true,
   };
 
+  // Polyfill node modules when platform is not node
+  if (!isNode) {
+    // @ts-expect-error Types dont match
+    config.plugins!.unshift(nodePolyfills());
+  }
+
   // Analyze the bundle for debugging purposes
   if (features.analyze) {
     config.plugins!.push(

src/schemas.ts

@@ -9,6 +9,7 @@ import {
   FORMATS_NATIVE,
   FORMATS_NODE,
   PLATFORMS,
+  SUPPORTS,
 } from './constants';
 import {
   AnalyzeType,
@@ -52,12 +53,7 @@ const format = string<Format>(DEFAULT_FORMAT)
 
 // SUPPORT
 
-const support = string<Support>(DEFAULT_SUPPORT).oneOf([
-  'legacy',
-  'stable',
-  'current',
-  'experimental',
-]);
+const support = string<Support>(DEFAULT_SUPPORT).oneOf(SUPPORTS);
 
 // BLUEPRINTS
 

tests/__fixtures__/examples/async-await.ts

@@ -0,0 +1,13 @@
+export async function wait() {
+  return new Promise((resolve) => {
+    setTimeout(resolve, 100);
+  });
+}
+
+export async function run() {
+  try {
+    await wait();
+  } catch {
+    throw new Error();
+  }
+}

tests/__fixtures__/examples/generators.ts

@@ -0,0 +1,7 @@
+export function* gen() {}
+
+export function runGen() {
+  for (const iterator of gen()) {
+    console.log(iterator);
+  }
+}

tests/__fixtures__/examples/node-polyfills.ts

@@ -0,0 +1,10 @@
+import path from 'path';
+import { EventEmitter } from 'events';
+
+export const test = path.join('foo', 'bar');
+
+export const emitter = new EventEmitter();
+
+export class Example extends EventEmitter {
+  log() {}
+}

tests/__fixtures__/examples/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "examples"
+}