Add support for ES Module and CommonJS output, and <script type="module">

packages/core/core/src/BundleGraph.js

@@ -21,7 +21,7 @@ import type Graph from './Graph';
 import invariant from 'assert';
 import crypto from 'crypto';
 import nullthrows from 'nullthrows';
-import {flatMap} from '@parcel/utils';
+import {flatMap, objectSortedEntriesDeep} from '@parcel/utils';
 
 import {getBundleGroupId} from './utils';
 import {mapVisitor} from './Graph';
@@ -509,6 +509,27 @@ export default class BundleGraph {
     return {asset, exportSymbol: symbol, symbol: identifier};
   }
 
+  getExportedSymbols(asset: Asset) {
+    let symbols = [];
+
+    for (let symbol of asset.symbols.keys()) {
+      symbols.push(this.resolveSymbol(asset, symbol));
+    }
+
+    let deps = this.getDependencies(asset);
+    for (let dep of deps) {
+      if (dep.symbols.get('*') === '*') {
+        let resolved = nullthrows(this.getDependencyResolution(dep));
+        let exported = this.getExportedSymbols(resolved).filter(
+          s => s.exportSymbol !== 'default'
+        );
+        symbols.push(...exported);
+      }
+    }
+
+    return symbols;
+  }
+
   getContentHash(bundle: Bundle): string {
     let existingHash = this._bundleContentHashes.get(bundle.id);
     if (existingHash != null) {
@@ -532,6 +553,7 @@ export default class BundleGraph {
       hash.update(this.getContentHash(childBundle));
     }, bundle);
 
+    hash.update(JSON.stringify(objectSortedEntriesDeep(bundle.env)));
     return hash.digest('hex');
   }
 }

packages/core/core/src/Environment.js

@@ -10,7 +10,9 @@ const DEFAULT_ENGINES = {
 export function createEnvironment({
   context,
   engines,
-  includeNodeModules
+  includeNodeModules,
+  outputFormat,
+  isLibrary = false
 }: EnvironmentOpts = {}): Environment {
   if (context == null) {
     if (engines?.node) {
@@ -59,10 +61,25 @@ export function createEnvironment({
     }
   }
 
+  if (outputFormat == null) {
+    switch (context) {
+      case 'node':
+      case 'electron-main':
+      case 'electron-renderer':
+        outputFormat = 'commonjs';
+        break;
+      default:
+        outputFormat = 'global';
+        break;
+    }
+  }
+
   return {
     context,
     engines,
-    includeNodeModules
+    includeNodeModules,
+    outputFormat,
+    isLibrary
   };
 }
 
@@ -75,8 +92,8 @@ export function mergeEnvironments(
     return a;
   }
 
-  return {
+  return createEnvironment({
     ...a,
     ...b
-  };
+  });
 }

packages/core/core/src/RequestGraph.js

@@ -237,7 +237,9 @@ export default class RequestGraph extends Graph<RequestGraphNode> {
       case 'dep_path_request':
         promise = this.queue.add(() =>
           this.resolvePath(requestNode.value).then(result => {
-            this.onDepPathRequestComplete(requestNode, result);
+            if (result) {
+              this.onDepPathRequestComplete(requestNode, result);
+            }
             return result;
           })
         );
@@ -315,18 +317,11 @@ export default class RequestGraph extends Graph<RequestGraphNode> {
   }
 
   async resolvePath(dep: Dependency) {
-    try {
-      let assetRequest = await this.resolverRunner.resolve(dep);
-
+    let assetRequest = await this.resolverRunner.resolve(dep);
+    if (assetRequest) {
       this.connectFile(nodeFromDepPathRequest(dep), assetRequest.filePath);
-      return assetRequest;
-    } catch (err) {
-      if (err.code === 'MODULE_NOT_FOUND' && dep.isOptional) {
-        return null;
-      }
-
-      throw err;
     }
+    return assetRequest;
   }
 
   async loadConfig(configRequest: ConfigRequest, parentNodeId: NodeId) {

packages/core/core/src/ResolverRunner.js

@@ -23,7 +23,7 @@ export default class ResolverRunner {
     this.pluginOptions = new PluginOptions(this.options);
   }
 
-  async resolve(dependency: Dependency): Promise<AssetRequest> {
+  async resolve(dependency: Dependency): Promise<?AssetRequest> {
     let dep = new PublicDependency(dependency);
     report({
       type: 'buildProgress',
@@ -39,14 +39,24 @@ export default class ResolverRunner {
         options: this.pluginOptions
       });
 
-      if (result) {
+      if (result && result.isExcluded) {
+        return null;
+      }
+
+      if (result && result.filePath) {
         return {
-          ...result,
+          filePath: result.filePath,
+          sideEffects: result.sideEffects,
+          code: result.code,
           env: dependency.env
         };
       }
     }
 
+    if (dep.isOptional) {
+      return null;
+    }
+
     let dir = dependency.sourcePath
       ? path.dirname(dependency.sourcePath)
       : '<none>';

packages/core/core/src/TargetResolver.js

@@ -169,6 +169,20 @@ export default class TargetResolver {
       pkg.browser || pkgTargets.browser || (node && !browsers)
         ? 'node'
         : 'browser';
+    let moduleContext =
+      pkg.browser || pkgTargets.browser ? 'browser' : mainContext;
+
+    let defaultEngines =
+      options.defaultEngines ??
+      (options.mode === 'production'
+        ? DEFAULT_PRODUCTION_ENGINES
+        : DEFAULT_DEVELOPMENT_ENGINES);
+    let context = browsers || !node ? 'browser' : 'node';
+    if (context === 'browser' && pkgEngines.browsers == null) {
+      pkgEngines.browsers = defaultEngines.browsers;
+    } else if (context === 'node' && pkgEngines.node == null) {
+      pkgEngines.node = defaultEngines.node;
+    }
 
     for (let targetName of COMMON_TARGETS) {
       let targetDist;
@@ -204,8 +218,16 @@ export default class TargetResolver {
             engines: descriptor.engines ?? pkgEngines,
             context:
               descriptor.context ??
-              (targetName === 'browser' ? 'browser' : mainContext),
-            includeNodeModules: descriptor.includeNodeModules
+              (targetName === 'browser'
+                ? 'browser'
+                : targetName === 'module'
+                ? moduleContext
+                : mainContext),
+            includeNodeModules: descriptor.includeNodeModules ?? false,
+            outputFormat:
+              descriptor.outputFormat ??
+              (targetName === 'module' ? 'esmodule' : 'commonjs'),
+            isLibrary: true
           }),
           sourceMap: descriptor.sourceMap
         });
@@ -218,6 +240,7 @@ export default class TargetResolver {
         continue;
       }
 
+      let descriptor = pkgTargets[name];
       let distPath = pkg[name];
       let distDir;
       let distEntry;
@@ -228,7 +251,6 @@ export default class TargetResolver {
         distEntry = path.basename(distPath);
       }
 
-      let descriptor = pkgTargets[name];
       if (descriptor) {
         targets.set(name, {
           name,
@@ -238,7 +260,9 @@ export default class TargetResolver {
           env: createEnvironment({
             engines: descriptor.engines ?? pkgEngines,
             context: descriptor.context,
-            includeNodeModules: descriptor.includeNodeModules
+            includeNodeModules: descriptor.includeNodeModules,
+            outputFormat: descriptor.outputFormat,
+            isLibrary: descriptor.isLibrary
           }),
           sourceMap: descriptor.sourceMap
         });
@@ -247,19 +271,6 @@ export default class TargetResolver {
 
     // If no explicit targets were defined, add a default.
     if (targets.size === 0) {
-      let context = browsers || !node ? 'browser' : 'node';
-      let defaultEngines =
-        options.defaultEngines ??
-        (options.mode === 'production'
-          ? DEFAULT_PRODUCTION_ENGINES
-          : DEFAULT_DEVELOPMENT_ENGINES);
-
-      if (context === 'browser' && pkgEngines.browsers == null) {
-        pkgEngines.browsers = defaultEngines.browsers;
-      } else if (context === 'node' && pkgEngines.node == null) {
-        pkgEngines.node = defaultEngines.node;
-      }
-
       targets.set('default', {
         name: 'default',
         distDir: path.resolve(this.fs.cwd(), DEFAULT_DIST_DIRNAME),

packages/core/core/src/Transformation.js

@@ -414,13 +414,15 @@ class Pipeline {
     preloadedConfig: ?Config
   ): Promise<Array<TransformerResult>> {
     const resolve = async (from: FilePath, to: string): Promise<FilePath> => {
-      return (await this.resolverRunner.resolve(
-        createDependency({
-          env: asset.value.env,
-          moduleSpecifier: to,
-          sourcePath: from
-        })
-      )).filePath;
+      return nullthrows(
+        await this.resolverRunner.resolve(
+          createDependency({
+            env: asset.value.env,
+            moduleSpecifier: to,
+            sourcePath: from
+          })
+        )
+      ).filePath;
     };
 
     // Load config for the transformer.

packages/core/core/src/public/BundleGraph.js

@@ -7,7 +7,8 @@ import type {
   BundleGroup,
   Dependency as IDependency,
   GraphTraversalCallback,
-  Symbol
+  Symbol,
+  SymbolResolution
 } from '@parcel/types';
 import type {ParcelOptions} from '../types';
 import type InternalBundleGraph from '../BundleGraph';
@@ -123,7 +124,7 @@ export default class BundleGraph implements IBundleGraph {
       .map(bundle => new Bundle(bundle, this.#graph, this.#options));
   }
 
-  resolveSymbol(asset: IAsset, symbol: Symbol) {
+  resolveSymbol(asset: IAsset, symbol: Symbol): SymbolResolution {
     let res = this.#graph.resolveSymbol(
       assetToInternalAsset(asset).value,
       symbol
@@ -135,6 +136,15 @@ export default class BundleGraph implements IBundleGraph {
     };
   }
 
+  getExportedSymbols(asset: IAsset): Array<SymbolResolution> {
+    let res = this.#graph.getExportedSymbols(assetToInternalAsset(asset).value);
+    return res.map(e => ({
+      asset: assetFromValue(e.asset, this.#options),
+      exportSymbol: e.exportSymbol,
+      symbol: e.symbol
+    }));
+  }
+
   traverseBundles<TContext>(
     visit: GraphTraversalCallback<IBundle, TContext>
   ): ?TContext {
@@ -145,4 +155,10 @@ export default class BundleGraph implements IBundleGraph {
       )
     );
   }
+
+  findBundlesWithAsset(asset: IAsset): Array<IBundle> {
+    return this.#graph
+      .findBundlesWithAsset(assetToInternalAsset(asset).value)
+      .map(bundle => new Bundle(bundle, this.#graph, this.#options));
+  }
 }