Merge pull request #15446 from webpack/feature/import-meta-webpack-context

import.meta.webpackContext

lib/WebpackOptionsApply.js

@@ -35,6 +35,7 @@ const ResolverCachePlugin = require("./cache/ResolverCachePlugin");
 
 const CommonJsPlugin = require("./dependencies/CommonJsPlugin");
 const HarmonyModulesPlugin = require("./dependencies/HarmonyModulesPlugin");
+const ImportMetaContextPlugin = require("./dependencies/ImportMetaContextPlugin");
 const ImportMetaPlugin = require("./dependencies/ImportMetaPlugin");
 const ImportPlugin = require("./dependencies/ImportPlugin");
 const LoaderPlugin = require("./dependencies/LoaderPlugin");
@@ -361,6 +362,7 @@ class WebpackOptionsApply extends OptionsApply {
 		new RequireEnsurePlugin().apply(compiler);
 		new RequireContextPlugin().apply(compiler);
 		new ImportPlugin().apply(compiler);
+		new ImportMetaContextPlugin().apply(compiler);
 		new SystemPlugin().apply(compiler);
 		new ImportMetaPlugin().apply(compiler);
 		new URLPlugin().apply(compiler);

lib/dependencies/ContextDependencyHelpers.js

@@ -37,7 +37,7 @@ const splitContextFromPrefix = prefix => {
 	};
 };
 
-/** @typedef {Partial<Omit<ContextDependencyOptions, "resource"|"recursive"|"regExp">>} PartialContextDependencyOptions */
+/** @typedef {Partial<Omit<ContextDependencyOptions, "resource">>} PartialContextDependencyOptions */
 
 /** @typedef {{ new(options: ContextDependencyOptions, range: [number, number], valueRange: [number, number]): ContextDependency }} ContextDependencyConstructor */
 

lib/dependencies/ImportContextDependency.js

@@ -28,7 +28,6 @@ class ImportContextDependency extends ContextDependency {
 	serialize(context) {
 		const { write } = context;
 
-		write(this.range);
 		write(this.valueRange);
 
 		super.serialize(context);
@@ -37,7 +36,6 @@ class ImportContextDependency extends ContextDependency {
 	deserialize(context) {
 		const { read } = context;
 
-		this.range = read();
 		this.valueRange = read();
 
 		super.deserialize(context);

lib/dependencies/ImportMetaContextDependency.js

@@ -0,0 +1,35 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Ivan Kopeykin @vankop
+*/
+
+"use strict";
+
+const makeSerializable = require("../util/makeSerializable");
+const ContextDependency = require("./ContextDependency");
+const ModuleDependencyTemplateAsRequireId = require("./ModuleDependencyTemplateAsRequireId");
+
+class ImportMetaContextDependency extends ContextDependency {
+	constructor(options, range) {
+		super(options);
+
+		this.range = range;
+	}
+
+	get category() {
+		return "esm";
+	}
+
+	get type() {
+		return `import.meta.webpackContext ${this.options.mode}`;
+	}
+}
+
+makeSerializable(
+	ImportMetaContextDependency,
+	"webpack/lib/dependencies/ImportMetaContextDependency"
+);
+
+ImportMetaContextDependency.Template = ModuleDependencyTemplateAsRequireId;
+
+module.exports = ImportMetaContextDependency;

lib/dependencies/ImportMetaContextDependencyParserPlugin.js

@@ -0,0 +1,252 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Ivan Kopeykin @vankop
+*/
+
+"use strict";
+
+const WebpackError = require("../WebpackError");
+const {
+	evaluateToIdentifier
+} = require("../javascript/JavascriptParserHelpers");
+const ImportMetaContextDependency = require("./ImportMetaContextDependency");
+
+/** @typedef {import("estree").Expression} ExpressionNode */
+/** @typedef {import("estree").ObjectExpression} ObjectExpressionNode */
+/** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */
+/** @typedef {import("../ContextModule").ContextModuleOptions} ContextModuleOptions */
+/** @typedef {import("../ChunkGroup").RawChunkGroupOptions} RawChunkGroupOptions */
+/** @typedef {Pick<ContextModuleOptions, 'mode'|'recursive'|'regExp'|'include'|'exclude'|'chunkName'>&{groupOptions: RawChunkGroupOptions, exports?: ContextModuleOptions["referencedExports"]}} ImportMetaContextOptions */
+
+function createPropertyParseError(prop, expect) {
+	return createError(
+		`Parsing import.meta.webpackContext options failed. Unknown value for property ${JSON.stringify(
+			prop.key.name
+		)}, expected type ${expect}.`,
+		prop.value.loc
+	);
+}
+
+function createError(msg, loc) {
+	const error = new WebpackError(msg);
+	error.name = "ImportMetaContextError";
+	error.loc = loc;
+	return error;
+}
+
+module.exports = class ImportMetaContextDependencyParserPlugin {
+	apply(parser) {
+		parser.hooks.evaluateIdentifier
+			.for("import.meta.webpackContext")
+			.tap("HotModuleReplacementPlugin", expr => {
+				return evaluateToIdentifier(
+					"import.meta.webpackContext",
+					"import.meta",
+					() => ["webpackContext"],
+					true
+				)(expr);
+			});
+		parser.hooks.call
+			.for("import.meta.webpackContext")
+			.tap("ImportMetaContextDependencyParserPlugin", expr => {
+				if (expr.arguments.length < 1 || expr.arguments.length > 2) return;
+				const [directoryNode, optionsNode] = expr.arguments;
+				if (optionsNode && optionsNode.type !== "ObjectExpression") return;
+				const requestExpr = parser.evaluateExpression(directoryNode);
+				if (!requestExpr.isString()) return;
+				const request = requestExpr.string;
+				const errors = [];
+				let regExp = /^\.\/.*$/;
+				let recursive = true;
+				/** @type {ContextModuleOptions["mode"]} */
+				let mode = "sync";
+				/** @type {ContextModuleOptions["include"]} */
+				let include;
+				/** @type {ContextModuleOptions["exclude"]} */
+				let exclude;
+				/** @type {RawChunkGroupOptions} */
+				const groupOptions = {};
+				/** @type {ContextModuleOptions["chunkName"]} */
+				let chunkName;
+				/** @type {ContextModuleOptions["referencedExports"]} */
+				let exports;
+				if (optionsNode) {
+					for (const prop of optionsNode.properties) {
+						if (prop.type !== "Property" || prop.key.type !== "Identifier") {
+							errors.push(
+								createError(
+									"Parsing import.meta.webpackContext options failed.",
+									optionsNode.loc
+								)
+							);
+							break;
+						}
+						switch (prop.key.name) {
+							case "regExp": {
+								const regExpExpr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (!regExpExpr.isRegExp()) {
+									errors.push(createPropertyParseError(prop, "RegExp"));
+								} else {
+									regExp = regExpExpr.regExp;
+								}
+								break;
+							}
+							case "include": {
+								const regExpExpr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (!regExpExpr.isRegExp()) {
+									errors.push(createPropertyParseError(prop, "RegExp"));
+								} else {
+									include = regExpExpr.regExp;
+								}
+								break;
+							}
+							case "exclude": {
+								const regExpExpr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (!regExpExpr.isRegExp()) {
+									errors.push(createPropertyParseError(prop, "RegExp"));
+								} else {
+									exclude = regExpExpr.regExp;
+								}
+								break;
+							}
+							case "mode": {
+								const modeExpr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (!modeExpr.isString()) {
+									errors.push(createPropertyParseError(prop, "string"));
+								} else {
+									mode = /** @type {ContextModuleOptions["mode"]} */ (
+										modeExpr.string
+									);
+								}
+								break;
+							}
+							case "chunkName": {
+								const expr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (!expr.isString()) {
+									errors.push(createPropertyParseError(prop, "string"));
+								} else {
+									chunkName = expr.string;
+								}
+								break;
+							}
+							case "exports": {
+								const expr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (expr.isString()) {
+									exports = [[expr.string]];
+								} else if (expr.isArray()) {
+									const items = expr.items;
+									if (
+										items.every(i => {
+											if (!i.isArray()) return false;
+											const innerItems = i.items;
+											return innerItems.every(i => i.isString());
+										})
+									) {
+										exports = [];
+										for (const i1 of items) {
+											const export_ = [];
+											for (const i2 of i1.items) {
+												export_.push(i2.string);
+											}
+											exports.push(export_);
+										}
+									} else {
+										errors.push(
+											createPropertyParseError(prop, "string|string[][]")
+										);
+									}
+								} else {
+									errors.push(
+										createPropertyParseError(prop, "string|string[][]")
+									);
+								}
+								break;
+							}
+							case "prefetch": {
+								const expr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (expr.isBoolean()) {
+									groupOptions.prefetchOrder = 0;
+								} else if (expr.isNumber()) {
+									groupOptions.prefetchOrder = expr.number;
+								} else {
+									errors.push(createPropertyParseError(prop, "boolean|number"));
+								}
+								break;
+							}
+							case "preload": {
+								const expr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (expr.isBoolean()) {
+									groupOptions.preloadOrder = 0;
+								} else if (expr.isNumber()) {
+									groupOptions.preloadOrder = expr.number;
+								} else {
+									errors.push(createPropertyParseError(prop, "boolean|number"));
+								}
+								break;
+							}
+							case "recursive": {
+								const recursiveExpr = parser.evaluateExpression(
+									/** @type {ExpressionNode} */ (prop.value)
+								);
+								if (!recursiveExpr.isBoolean()) {
+									errors.push(createPropertyParseError(prop, "boolean"));
+								} else {
+									recursive = recursiveExpr.bool;
+								}
+								break;
+							}
+							default:
+								errors.push(
+									createError(
+										`Parsing import.meta.webpackContext options failed. Unknown property ${JSON.stringify(
+											prop.key.name
+										)}.`,
+										optionsNode.loc
+									)
+								);
+						}
+					}
+				}
+				if (errors.length) {
+					for (const error of errors) parser.state.current.addError(error);
+					return;
+				}
+
+				const dep = new ImportMetaContextDependency(
+					{
+						request,
+						include,
+						exclude,
+						recursive,
+						regExp,
+						groupOptions,
+						chunkName,
+						referencedExports: exports,
+						mode,
+						category: "esm"
+					},
+					expr.range
+				);
+				dep.loc = expr.loc;
+				dep.optional = !!parser.scope.inTry;
+				parser.state.current.addDependency(dep);
+				return true;
+			});
+	}
+};

lib/dependencies/ImportMetaContextPlugin.js

@@ -0,0 +1,59 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Ivan Kopeykin @vankop
+*/
+
+"use strict";
+
+const ContextElementDependency = require("./ContextElementDependency");
+const ImportMetaContextDependency = require("./ImportMetaContextDependency");
+const ImportMetaContextDependencyParserPlugin = require("./ImportMetaContextDependencyParserPlugin");
+
+/** @typedef {import("../../declarations/WebpackOptions").ResolveOptions} ResolveOptions */
+/** @typedef {import("../Compiler")} Compiler */
+
+class ImportMetaContextPlugin {
+	/**
+	 * Apply the plugin
+	 * @param {Compiler} compiler the compiler instance
+	 * @returns {void}
+	 */
+	apply(compiler) {
+		compiler.hooks.compilation.tap(
+			"RequireContextPlugin",
+			(compilation, { contextModuleFactory, normalModuleFactory }) => {
+				compilation.dependencyFactories.set(
+					ImportMetaContextDependency,
+					contextModuleFactory
+				);
+				compilation.dependencyTemplates.set(
+					ImportMetaContextDependency,
+					new ImportMetaContextDependency.Template()
+				);
+				compilation.dependencyFactories.set(
+					ContextElementDependency,
+					normalModuleFactory
+				);
+
+				const handler = (parser, parserOptions) => {
+					if (
+						parserOptions.importMetaContext !== undefined &&
+						!parserOptions.importMetaContext
+					)
+						return;
+
+					new ImportMetaContextDependencyParserPlugin().apply(parser);
+				};
+
+				normalModuleFactory.hooks.parser
+					.for("javascript/auto")
+					.tap("ImportMetaContextPlugin", handler);
+				normalModuleFactory.hooks.parser
+					.for("javascript/esm")
+					.tap("ImportMetaContextPlugin", handler);
+			}
+		);
+	}
+}
+
+module.exports = ImportMetaContextPlugin;

lib/dependencies/RequireContextDependency.js

@@ -19,22 +19,6 @@ class RequireContextDependency extends ContextDependency {
 	get type() {
 		return "require.context";
 	}
-
-	serialize(context) {
-		const { write } = context;
-
-		write(this.range);
-
-		super.serialize(context);
-	}
-
-	deserialize(context) {
-		const { read } = context;
-
-		this.range = read();
-
-		super.deserialize(context);
-	}
 }
 
 makeSerializable(

lib/util/internalSerializables.js

@@ -126,6 +126,8 @@ module.exports = {
 		require("../dependencies/ImportMetaHotAcceptDependency"),
 	"dependencies/ImportMetaHotDeclineDependency": () =>
 		require("../dependencies/ImportMetaHotDeclineDependency"),
+	"dependencies/ImportMetaContextDependency": () =>
+		require("../dependencies/ImportMetaContextDependency"),
 	"dependencies/ProvidedDependency": () =>
 		require("../dependencies/ProvidedDependency"),
 	"dependencies/PureExpressionDependency": () =>

module.d.ts

@@ -148,6 +148,20 @@ interface ImportMeta {
 	url: string;
 	webpack: number;
 	webpackHot: webpack.Hot;
+	webpackContext: (
+		request: string,
+		options?: {
+			recursive?: boolean;
+			regExp?: RegExp;
+			include?: RegExp;
+			exclude?: RegExp;
+			preload?: boolean | number;
+			prefetch?: boolean | number;
+			chunkName?: string;
+			exports?: string | string[][];
+			mode?: "sync" | "eager" | "weak" | "lazy" | "lazy-once";
+		}
+	) => webpack.Context;
 }
 
 declare const __resourceQuery: string;

test/cases/chunks/context-weak/index.js

@@ -5,6 +5,17 @@ it("should not bundle context requires with asyncMode === 'weak'", function() {
 	}).toThrowError(/not available/);
 });
 
+it("should not bundle context requires with asyncMode === 'weak' using import.meta.webpackContext", function() {
+	const contextRequire = import.meta.webpackContext(".", {
+		recursive: false,
+		regExp: /two/,
+		mode: "weak"
+	});
+	expect(function() {
+		contextRequire("./two")
+	}).toThrowError(/not available/);
+});
+
 it("should find module with asyncMode === 'weak' when required elsewhere", function() {
 	var contextRequire = require.context(".", false, /.+/, "weak");
 	expect(contextRequire("./three")).toBe(3);

test/cases/context/import-meta-webpack-context/dir/four.js

@@ -0,0 +1 @@
+module.exports = 4;

test/cases/context/import-meta-webpack-context/index.js

@@ -0,0 +1,27 @@
+it("should allow prefetch/preload", function() {
+	const contextRequire = import.meta.webpackContext("./dir", {
+		prefetch: true,
+		preload: 1
+	});
+	expect(contextRequire("./four")).toBe(4);
+});
+
+it("should allow include/exclude", function() {
+	const contextRequire = import.meta.webpackContext(".", {
+		recursive: false,
+		regExp: /two/,
+		mode: "weak",
+		exclude: /three/
+	});
+	expect(function() {
+		contextRequire("./two-three")
+	}).toThrowError(/Cannot find module/);
+});
+
+it("should allow chunkName", function() {
+	const contextRequire = import.meta.webpackContext(".", {
+		regExp: /two-three/,
+		chunkName: "chunk012"
+	});
+	expect(contextRequire("./two-three")).toBe(3);
+});

test/cases/context/import-meta-webpack-context/two-three.js

@@ -0,0 +1 @@
+module.exports = 3;

test/cases/context/import-meta-webpack-context/two.js

@@ -0,0 +1 @@
+module.exports = 2;