optimize storage format of ExportMode

lib/dependencies/HarmonyExportImportedSpecifierDependency.js

@@ -33,12 +33,6 @@ const HarmonyImportDependency = require("./HarmonyImportDependency");
 
 const idsSymbol = Symbol("HarmonyExportImportedSpecifierDependency.ids");
 
-/** @type {Map<string, string[]>} */
-const EMPTY_MAP = new Map();
-
-/** @type {Set<string>} */
-const EMPTY_SET = new Set();
-
 /**
  * @param {string[][]} referencedExports list of referenced exports, will be added to
  * @param {string[]} prefix export prefix
@@ -82,6 +76,21 @@ const processExportInfo = (
 	}
 };
 
+class NormalReexportItem {
+	/**
+	 * @param {string} name export name
+	 * @param {string[]} ids reexported ids from other module
+	 * @param {ExportInfo=} exportInfo export info from other module
+	 * @param {boolean} checked true, if it should be checked at runtime if this export exists
+	 */
+	constructor(name, ids, exportInfo, checked) {
+		this.name = name;
+		this.ids = ids;
+		this.exportInfo = exportInfo;
+		this.checked = checked;
+	}
+}
+
 class ExportMode {
 	/**
 	 * @param {ExportModeType} type type of the mode
@@ -89,18 +98,26 @@ class ExportMode {
 	constructor(type) {
 		/** @type {ExportModeType} */
 		this.type = type;
+
+		// for "normal-reexport":
+		/** @type {NormalReexportItem[] | null} */
+		this.items = null;
+
+		// for "reexport-named-default" | "reexport-fake-namespace-object" | "reexport-namespace-object"
 		/** @type {string|null} */
 		this.name = null;
-		/** @type {Map<string, string[]>} */
-		this.map = EMPTY_MAP;
-		/** @type {Map<string, ExportInfo>|undefined|ExportInfo} */
-		this.partialNamespaceExportInfo = undefined;
-		/** @type {Set<string>|null} */
+		/** @type {ExportInfo | null} */
+		this.partialNamespaceExportInfo = null;
+
+		// for "dynamic-reexport":
+		/** @type {Set<string> | null} */
 		this.ignored = null;
-		/** @type {Set<string>|null} */
-		this.checked = null;
-		/** @type {string|null} */
+
+		// for "missing":
+		/** @type {string | null} */
 		this.userRequest = null;
+
+		// for "reexport-fake-namespace-object":
 		/** @type {number} */
 		this.fakeType = 0;
 	}
@@ -245,10 +262,7 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 						break;
 					default:
 						mode = new ExportMode("normal-reexport");
-						mode.map = new Map([[name, ids]]);
-						mode.partialNamespaceExportInfo = new Map();
-						mode.partialNamespaceExportInfo.set(name, exportInfo);
-						mode.checked = EMPTY_SET;
+						mode.items = [new NormalReexportItem(name, ids, exportInfo, false)];
 						break;
 				}
 			} else {
@@ -305,23 +319,18 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 			return mode;
 		}
 
-		/** @type {Map<string, string[]>} */
-		const map = new Map();
-		/** @type {Map<string, ExportInfo>} */
-		const exportsInfoMap = new Map();
-		for (const exportName of exports) {
-			map.set(exportName, [exportName]);
-			exportsInfoMap.set(
-				exportName,
-				exportsInfo.getReadOnlyExportInfo(exportName)
-			);
-		}
-
 		const mode = new ExportMode("normal-reexport");
 
-		mode.map = map;
-		mode.partialNamespaceExportInfo = exportsInfoMap;
-		mode.checked = checked;
+		mode.items = Array.from(
+			exports,
+			exportName =>
+				new NormalReexportItem(
+					exportName,
+					[exportName],
+					exportsInfo.getReadOnlyExportInfo(exportName),
+					checked.has(exportName)
+				)
+		);
 
 		return mode;
 	}
@@ -452,17 +461,10 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 				return Dependency.EXPORTS_OBJECT_REFERENCED;
 
 			case "normal-reexport": {
-				if (!mode.partialNamespaceExportInfo)
-					return Array.from(mode.map.values());
-
 				const referencedExports = [];
-				for (const [key, value] of mode.map) {
-					const exportInfo = /** @type {Map<string, ExportInfo>} */ (mode.partialNamespaceExportInfo).get(
-						key
-					);
-					processExportInfo(referencedExports, value, exportInfo, false);
+				for (const { ids, exportInfo } of mode.items) {
+					processExportInfo(referencedExports, ids, exportInfo, false);
 				}
-
 				return referencedExports;
 			}
 
@@ -523,15 +525,17 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 					exports: [],
 					dependencies: [moduleGraph.getModule(this)]
 				};
-			case "normal-reexport":
+			case "normal-reexport": {
+				const from = moduleGraph.getModule(this);
 				return {
-					exports: Array.from(mode.map.keys()).map(name => ({
-						name,
-						from: moduleGraph.getModule(this),
-						export: mode.map.get(name)
+					exports: Array.from(mode.items, item => ({
+						name: item.name,
+						from,
+						export: item.ids
 					})),
-					dependencies: [moduleGraph.getModule(this)]
+					dependencies: [from]
 				};
+			}
 			case "reexport-dynamic-default":
 			case "reexport-undefined":
 				return {
@@ -641,9 +645,12 @@ class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
 		const mode = this.getMode(chunkGraph.moduleGraph);
 
 		hash.update(mode.type);
-		for (const [k, v] of mode.map) {
-			hash.update(k);
-			hash.update(v.join());
+		if (mode.items) {
+			for (const item of mode.items) {
+				hash.update(item.name);
+				hash.update(item.ids.join());
+				if (item.checked) hash.update("checked");
+			}
 		}
 		if (mode.ignored) {
 			hash.update("ignored");
@@ -824,16 +831,16 @@ HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedS
 				break;
 
 			case "normal-reexport":
-				for (const [key, id] of mode.map) {
-					if (mode.checked.has(key)) {
+				for (const { name, ids, checked } of mode.items) {
+					if (checked) {
 						initFragments.push(
 							new InitFragment(
 								"/* harmony reexport (checked) */ " +
 									this.getConditionalReexportStatement(
 										module,
-										key,
+										name,
 										importVar,
-										id,
+										ids,
 										runtimeRequirements
 									),
 								InitFragment.STAGE_HARMONY_IMPORTS,
@@ -845,9 +852,9 @@ HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedS
 							this.getReexportFragment(
 								module,
 								"reexport safe",
-								module.getUsedName(moduleGraph, key),
+								module.getUsedName(moduleGraph, name),
 								importVar,
-								importedModule.getUsedName(moduleGraph, id),
+								importedModule.getUsedName(moduleGraph, ids),
 								runtimeRequirements
 							)
 						);

lib/optimize/SideEffectsFlagPlugin.js

@@ -214,15 +214,15 @@ class SideEffectsFlagPlugin {
 										const targetModule = moduleGraph.getModule(dep);
 										switch (mode.type) {
 											case "normal-reexport":
-												for (const [key, ids] of mode.map) {
+												for (const { name, ids, checked } of mode.items) {
 													// TODO Support reexporting namespace object
 													if (ids.length > 0) {
 														addStaticReexport(
 															info,
-															key,
+															name,
 															targetModule,
 															ids[0],
-															mode.checked.has(key)
+															checked
 														);
 													}
 												}

test/__snapshots__/StatsTestCases.test.js.snap

@@ -2738,7 +2738,7 @@ Entrypoint main = main.js
 `;
 
 exports[`StatsTestCases should print correct stats for side-effects-optimization 1`] = `
-"Hash: d7d1b4f45cd90d4abdb64369e7ea517dce8ffb09
+"Hash: d7d1b4f45cd90d4abdb6d61ad7aea717eb8e1363
 Child
     Hash: d7d1b4f45cd90d4abdb6
     Time: X ms
@@ -2762,7 +2762,7 @@ Child
         ModuleConcatenation bailout: Module is not an ECMAScript module
         + 2 hidden modules
 Child
-    Hash: 4369e7ea517dce8ffb09
+    Hash: d61ad7aea717eb8e1363
     Time: X ms
     Built at: 1970-04-20 12:42:42
               Asset      Size
@@ -3843,7 +3843,7 @@ chunk default/async-a.js (async-a) 134 bytes <{179}> [rendered]
 `;
 
 exports[`StatsTestCases should print correct stats for tree-shaking 1`] = `
-"Hash: 0653813b0ee99f2a94bd
+"Hash: cd2fbd230872570f58af
 Time: X ms
 Built at: 1970-04-20 12:42:42
     Asset      Size