Smaller performance improvements in NormalModuleFactory

lib/Compilation.js

@@ -808,6 +808,12 @@ class Compilation {
 			}
 		}
 
+		if (sortedDependencies.length === 0) {
+			callback();
+			return;
+		}
+
+		process.nextTick(() => {
 			// This is nested so we need to allow one additional task
 			this.processDependenciesQueue.increaseParallelism();
 
@@ -839,6 +845,7 @@ class Compilation {
 					return callback(err);
 				}
 			);
+		});
 	}
 
 	/**

lib/Compiler.js

@@ -566,6 +566,7 @@ class Compiler {
 			this.hooks.make.callAsync(compilation, err => {
 				if (err) return callback(err);
 
+				process.nextTick(() => {
 					compilation.finish(err => {
 						if (err) return callback(err);
 
@@ -581,6 +582,7 @@ class Compiler {
 					});
 				});
 			});
+		});
 	}
 
 	/**

lib/NormalModuleFactory.js

@@ -58,6 +58,14 @@ const loaderToIdent = data => {
 	return data.loader + "?" + JSON.stringify(data.options);
 };
 
+const stringifyLoadersAndResource = (loaders, resource) => {
+	let str = "";
+	for (const loader of loaders) {
+		str += loaderToIdent(loader) + "!";
+	}
+	return str + resource;
+};
+
 const identToLoaderRequest = resultString => {
 	const idx = resultString.indexOf("?");
 	if (idx >= 0) {
@@ -75,6 +83,18 @@ const identToLoaderRequest = resultString => {
 	}
 };
 
+const needCalls = (times, callback) => {
+	return err => {
+		if (--times === 0) {
+			return callback(err);
+		}
+		if (err && times > 0) {
+			times = NaN;
+			return callback(err);
+		}
+	};
+};
+
 // TODO webpack 6 remove
 const deprecationChangedHookMessage = name =>
 	`NormalModuleFactory.${name} is no longer a waterfall hook, but a bailing hook instead. ` +
@@ -196,25 +216,33 @@ class NormalModuleFactory extends ModuleFactory {
 				const matchResourceMatch = MATCH_RESOURCE_REGEX.exec(request);
 				if (matchResourceMatch) {
 					matchResource = matchResourceMatch[1];
-					if (/^\.\.?\//.test(matchResource)) {
+					if (matchResource.charCodeAt(0) === 46) {
+						// 46 === ".", 47 === "/"
+						const secondChar = matchResource.charCodeAt(1);
+						if (
+							secondChar === 47 ||
+							(secondChar === 46 && matchResource.charCodeAt(2) === 47)
+						) {
+							// if matchResources startsWith ../ or ./
 							matchResource = path.join(context, matchResource);
 						}
+					}
 					requestWithoutMatchResource = request.substr(
 						matchResourceMatch[0].length
 					);
 				}
 
-				const noPreAutoLoaders = requestWithoutMatchResource.startsWith("-!");
-				const noAutoLoaders =
-					noPreAutoLoaders || requestWithoutMatchResource.startsWith("!");
-				const noPrePostAutoLoaders = requestWithoutMatchResource.startsWith(
-					"!!"
-				);
+				const firstChar = requestWithoutMatchResource.charCodeAt(0);
+				const secondChar = requestWithoutMatchResource.charCodeAt(1);
+				const noPreAutoLoaders = firstChar === 45 && secondChar === 33; // startsWith "-!"
+				const noAutoLoaders = noPreAutoLoaders || firstChar === 33; // startsWith "!"
+				const noPrePostAutoLoaders = firstChar === 33 && secondChar === 33; // startsWith "!!";
 				const rawElements = requestWithoutMatchResource
-					.replace(/^-?!+/, "")
-					.replace(/!!+/g, "!")
-					.split("!");
-				const resource = rawElements.pop();
+					.slice(
+						noPreAutoLoaders || noPrePostAutoLoaders ? 2 : noAutoLoaders ? 1 : 0
+					)
+					.split(/!+/);
+				const unresolvedResource = rawElements.pop();
 				const elements = rawElements.map(identToLoaderRequest);
 
 				const resolveContext = {
@@ -224,58 +252,18 @@ class NormalModuleFactory extends ModuleFactory {
 					contextDependencies
 				};
 
-				asyncLib.parallel(
-					[
-						callback =>
-							this.resolveRequestArray(
-								contextInfo,
-								context,
-								elements,
-								loaderResolver,
-								resolveContext,
-								callback
-							),
-						callback => {
-							if (resource === "" || resource[0] === "?") {
-								return callback(null, {
-									resource
-								});
-							}
+				/** @type {string | false} */
+				let resource;
+				let resourceResolveData;
+				let loaders;
 
-							normalResolver.resolve(
-								contextInfo,
-								context,
-								resource,
-								resolveContext,
-								(err, resource, resourceResolveData) => {
+				const continueCallback = needCalls(2, err => {
 					if (err) return callback(err);
 
-									// TODO remove this when enhanced-resolve supports fileDependencies
-									if (resource) {
-										fileDependencies.add(resource);
-									}
-
-									callback(null, {
-										resourceResolveData,
-										resource
-									});
-								}
-							);
-						}
-					],
-					(err, results) => {
-						if (err) return callback(err);
-						let loaders = results[0];
-						const resourceResolveData = results[1].resourceResolveData;
-						const resource = results[1].resource;
-
 					// translate option idents
 					try {
 						for (const item of loaders) {
-								if (
-									typeof item.options === "string" &&
-									item.options[0] === "?"
-								) {
+							if (typeof item.options === "string" && item.options[0] === "?") {
 								const ident = item.options.substr(1);
 								item.options = this.ruleSet.findOptionsByIdent(ident);
 								item.ident = ident;
@@ -299,10 +287,7 @@ class NormalModuleFactory extends ModuleFactory {
 
 					const userRequest =
 						(matchResource !== undefined ? `${matchResource}!=!` : "") +
-							loaders
-								.map(loaderToIdent)
-								.concat([resource])
-								.join("!");
+						stringifyLoadersAndResource(loaders, resource);
 
 					let resourcePath =
 						matchResource !== undefined ? matchResource : resource;
@@ -355,48 +340,24 @@ class NormalModuleFactory extends ModuleFactory {
 							settings[r.type] = r.value;
 						}
 					}
-						asyncLib.parallel(
-							[
-								this.resolveRequestArray.bind(
-									this,
-									contextInfo,
-									this.context,
-									useLoadersPost,
-									loaderResolver,
-									resolveContext
-								),
-								this.resolveRequestArray.bind(
-									this,
-									contextInfo,
-									this.context,
-									useLoaders,
-									loaderResolver,
-									resolveContext
-								),
-								this.resolveRequestArray.bind(
-									this,
-									contextInfo,
-									this.context,
-									useLoadersPre,
-									loaderResolver,
-									resolveContext
-								)
-							],
-							(err, results) => {
+
+					let postLoaders, normalLoaders, preLoaders;
+
+					const continueCallback = needCalls(3, err => {
 						if (err) {
 							return callback(err);
 						}
-								loaders = results[0].concat(loaders, results[1], results[2]);
+						const allLoaders = postLoaders;
+						for (const loader of loaders) allLoaders.push(loader);
+						for (const loader of normalLoaders) allLoaders.push(loader);
+						for (const loader of preLoaders) allLoaders.push(loader);
 						const type = settings.type;
 						const resolveOptions = settings.resolve;
 						Object.assign(data.createData, {
-									request: loaders
-										.map(loaderToIdent)
-										.concat([resource])
-										.join("!"),
+							request: stringifyLoadersAndResource(allLoaders, resource),
 							userRequest,
 							rawRequest: request,
-									loaders,
+							loaders: allLoaders,
 							resource,
 							matchResource,
 							resourceResolveData,
@@ -407,8 +368,80 @@ class NormalModuleFactory extends ModuleFactory {
 							resolveOptions
 						});
 						callback();
+					});
+					this.resolveRequestArray(
+						contextInfo,
+						this.context,
+						useLoadersPost,
+						loaderResolver,
+						resolveContext,
+						(err, result) => {
+							postLoaders = result;
+							continueCallback(err);
 						}
 					);
+					this.resolveRequestArray(
+						contextInfo,
+						this.context,
+						useLoaders,
+						loaderResolver,
+						resolveContext,
+						(err, result) => {
+							normalLoaders = result;
+							continueCallback(err);
+						}
+					);
+					this.resolveRequestArray(
+						contextInfo,
+						this.context,
+						useLoadersPre,
+						loaderResolver,
+						resolveContext,
+						(err, result) => {
+							preLoaders = result;
+							continueCallback(err);
+						}
+					);
+				});
+
+				this.resolveRequestArray(
+					contextInfo,
+					context,
+					elements,
+					loaderResolver,
+					resolveContext,
+					(err, result) => {
+						if (err) return continueCallback(err);
+						loaders = result;
+						continueCallback();
+					}
+				);
+
+				if (
+					unresolvedResource === "" ||
+					unresolvedResource.charCodeAt(0) === 63
+				) {
+					// 63 === "?"
+					resource = unresolvedResource;
+					return continueCallback();
+				}
+
+				normalResolver.resolve(
+					contextInfo,
+					context,
+					unresolvedResource,
+					resolveContext,
+					(err, resolvedResource, resolvedResourceResolveData) => {
+						if (err) return continueCallback(err);
+
+						// TODO remove this when enhanced-resolve supports fileDependencies
+						if (resolvedResource) {
+							fileDependencies.add(resolvedResource);
+						}
+
+						resource = resolvedResource;
+						resourceResolveData = resolvedResourceResolveData;
+						continueCallback();
 					}
 				);
 			}
@@ -484,7 +517,7 @@ class NormalModuleFactory extends ModuleFactory {
 		resolveContext,
 		callback
 	) {
-		if (array.length === 0) return callback(null, []);
+		if (array.length === 0) return callback(null, array);
 		asyncLib.map(
 			array,
 			(item, callback) => {
@@ -503,7 +536,7 @@ class NormalModuleFactory extends ModuleFactory {
 								contextInfo,
 								context,
 								item.loader + "-loader",
-								{},
+								resolveContext,
 								err2 => {
 									if (!err2) {
 										err.message =
@@ -521,18 +554,15 @@ class NormalModuleFactory extends ModuleFactory {
 						}
 						if (err) return callback(err);
 
-						const optionsOnly = item.options
-							? {
-									options: item.options
-							  }
-							: undefined;
-
-						const resolved = Object.assign(
-							{},
-							item,
-							identToLoaderRequest(result),
-							optionsOnly
-						);
+						const parsedResult = identToLoaderRequest(result);
+						const resolved = {
+							loader: parsedResult.loader,
+							options:
+								item.options === undefined
+									? parsedResult.options
+									: item.options,
+							ident: item.options === undefined ? undefined : item.ident
+						};
 
 						// TODO remove this when enhanced-resolve supports fileDependencies
 						if (resolved.loader) {