webpack/lib/dependencies/ImportParserPlugin.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const AsyncDependenciesBlock = require("../AsyncDependenciesBlock");
const CommentCompilationWarning = require("../CommentCompilationWarning");
const UnsupportedFeatureWarning = require("../UnsupportedFeatureWarning");
const {
	VariableInfo,
	getImportAttributes
} = require("../javascript/JavascriptParser");
const traverseDestructuringAssignmentProperties = require("../util/traverseDestructuringAssignmentProperties");
const ContextDependencyHelpers = require("./ContextDependencyHelpers");
const ImportContextDependency = require("./ImportContextDependency");
const ImportDependency = require("./ImportDependency");
const ImportEagerDependency = require("./ImportEagerDependency");
const ImportWeakDependency = require("./ImportWeakDependency");

/** @typedef {import("../../declarations/WebpackOptions").JavascriptParserOptions} JavascriptParserOptions */
/** @typedef {import("../ChunkGroup").RawChunkGroupOptions} RawChunkGroupOptions */
/** @typedef {import("../ContextModule").ContextMode} ContextMode */
/** @typedef {import("../Dependency").DependencyLocation} DependencyLocation */
/** @typedef {import("../Dependency").RawReferencedExports} RawReferencedExports */
/** @typedef {import("../Module").BuildMeta} BuildMeta */
/** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */
/** @typedef {import("../javascript/JavascriptParser").ImportExpression} ImportExpression */
/** @typedef {import("../javascript/JavascriptParser").Range} Range */
/** @typedef {import("../javascript/JavascriptParser").ParserState} ParserState */
/** @typedef {import("../javascript/JavascriptParser").Members} Members */
/** @typedef {import("../javascript/JavascriptParser").MembersOptionals} MembersOptionals */
/** @typedef {import("../javascript/JavascriptParser").ArrowFunctionExpression} ArrowFunctionExpression */
/** @typedef {import("../javascript/JavascriptParser").FunctionExpression} FunctionExpression */
/** @typedef {import("../javascript/JavascriptParser").Identifier} Identifier */
/** @typedef {import("../javascript/JavascriptParser").ObjectPattern} ObjectPattern */
/** @typedef {import("../javascript/JavascriptParser").CallExpression} CallExpression */

/** @typedef {{ references: RawReferencedExports, expression: ImportExpression }} ImportSettings */
/** @typedef {WeakMap<ImportExpression, RawReferencedExports>} State */

/** @type {WeakMap<ParserState, State>} */
const parserStateMap = new WeakMap();
const dynamicImportTag = Symbol("import()");

/**
 * @param {JavascriptParser} parser javascript parser
 * @returns {State} import parser plugin state
 */
function getState(parser) {
	if (!parserStateMap.has(parser.state)) {
		parserStateMap.set(parser.state, new WeakMap());
	}
	return /** @type {State} */ (parserStateMap.get(parser.state));
}

/**
 * @param {JavascriptParser} parser javascript parser
 * @param {ImportExpression} importCall import expression
 * @param {string} variableName variable name
 */
function tagDynamicImportReferenced(parser, importCall, variableName) {
	const state = getState(parser);
	/** @type {RawReferencedExports} */
	const references = state.get(importCall) || [];
	state.set(importCall, references);
	parser.tagVariable(
		variableName,
		dynamicImportTag,
		/** @type {ImportSettings} */ ({
			references,
			expression: importCall
		})
	);
}

/**
 * @param {CallExpression} importThen import().then() call
 * @returns {Identifier | ObjectPattern | undefined} the dynamic imported namespace obj
 */
function getFulfilledCallbackNamespaceObj(importThen) {
	const fulfilledCallback = importThen.arguments[0];
	if (
		fulfilledCallback &&
		(fulfilledCallback.type === "ArrowFunctionExpression" ||
			fulfilledCallback.type === "FunctionExpression") &&
		fulfilledCallback.params[0] &&
		(fulfilledCallback.params[0].type === "Identifier" ||
			fulfilledCallback.params[0].type === "ObjectPattern")
	) {
		return fulfilledCallback.params[0];
	}
}

/**
 * @param {JavascriptParser} parser javascript parser
 * @param {ImportExpression} importCall import expression
 * @param {ArrowFunctionExpression | FunctionExpression} fulfilledCallback the fulfilled callback
 * @param {Identifier | ObjectPattern} namespaceObjArg the argument of namespace object=
 */
function walkImportThenFulfilledCallback(
	parser,
	importCall,
	fulfilledCallback,
	namespaceObjArg
) {
	const arrow = fulfilledCallback.type === "ArrowFunctionExpression";
	const wasTopLevel = parser.scope.topLevelScope;
	parser.scope.topLevelScope = arrow ? (wasTopLevel ? "arrow" : false) : false;
	const scopeParams = [...fulfilledCallback.params];

	// Add function name in scope for recursive calls
	if (!arrow && fulfilledCallback.id) {
		scopeParams.push(fulfilledCallback.id);
	}

	parser.inFunctionScope(!arrow, scopeParams, () => {
		if (namespaceObjArg.type === "Identifier") {
			tagDynamicImportReferenced(parser, importCall, namespaceObjArg.name);
		} else {
			parser.enterDestructuringAssignment(namespaceObjArg, importCall);
			const referencedPropertiesInDestructuring =
				parser.destructuringAssignmentPropertiesFor(importCall);
			if (referencedPropertiesInDestructuring) {
				const state = getState(parser);
				const references = /** @type {RawReferencedExports} */ (
					state.get(importCall)
				);
				/** @type {RawReferencedExports} */
				const refsInDestructuring = [];
				traverseDestructuringAssignmentProperties(
					referencedPropertiesInDestructuring,
					(stack) => refsInDestructuring.push(stack.map((p) => p.id))
				);
				for (const ids of refsInDestructuring) {
					references.push(ids);
				}
			}
		}
		for (const param of fulfilledCallback.params) {
			parser.walkPattern(param);
		}
		if (fulfilledCallback.body.type === "BlockStatement") {
			parser.detectMode(fulfilledCallback.body.body);
			const prev = parser.prevStatement;
			parser.preWalkStatement(fulfilledCallback.body);
			parser.prevStatement = prev;
			parser.walkStatement(fulfilledCallback.body);
		} else {
			parser.walkExpression(fulfilledCallback.body);
		}
	});
	parser.scope.topLevelScope = wasTopLevel;
}

/**
 * @template T
 * @param {Iterable<T>} enumerable enumerable
 * @returns {T[][]} array of array
 */
const exportsFromEnumerable = (enumerable) =>
	Array.from(enumerable, (e) => [e]);

const PLUGIN_NAME = "ImportParserPlugin";

class ImportParserPlugin {
	/**
	 * @param {JavascriptParserOptions} options options
	 */
	constructor(options) {
		this.options = options;
	}

	/**
	 * @param {JavascriptParser} parser the parser
	 * @returns {void}
	 */
	apply(parser) {
		/**
		 * @param {Members} members members
		 * @param {MembersOptionals} membersOptionals members Optionals
		 * @returns {string[]} a non optional part
		 */
		function getNonOptionalPart(members, membersOptionals) {
			let i = 0;
			while (i < members.length && membersOptionals[i] === false) i++;
			return i !== members.length ? members.slice(0, i) : members;
		}

		parser.hooks.collectDestructuringAssignmentProperties.tap(
			PLUGIN_NAME,
			(expr) => {
				if (expr.type === "ImportExpression") return true;
				const nameInfo = parser.getNameForExpression(expr);
				if (
					nameInfo &&
					nameInfo.rootInfo instanceof VariableInfo &&
					nameInfo.rootInfo.name &&
					parser.getTagData(nameInfo.rootInfo.name, dynamicImportTag)
				) {
					return true;
				}
			}
		);
		parser.hooks.preDeclarator.tap(PLUGIN_NAME, (decl) => {
			if (
				decl.init &&
				decl.init.type === "AwaitExpression" &&
				decl.init.argument.type === "ImportExpression" &&
				decl.id.type === "Identifier"
			) {
				parser.defineVariable(decl.id.name);
				tagDynamicImportReferenced(parser, decl.init.argument, decl.id.name);
			}
		});
		parser.hooks.expression.for(dynamicImportTag).tap(PLUGIN_NAME, (expr) => {
			const settings = /** @type {ImportSettings} */ (parser.currentTagData);
			const referencedPropertiesInDestructuring =
				parser.destructuringAssignmentPropertiesFor(expr);
			if (referencedPropertiesInDestructuring) {
				/** @type {RawReferencedExports} */
				const refsInDestructuring = [];
				traverseDestructuringAssignmentProperties(
					referencedPropertiesInDestructuring,
					(stack) => refsInDestructuring.push(stack.map((p) => p.id))
				);
				for (const ids of refsInDestructuring) {
					settings.references.push(ids);
				}
			} else {
				settings.references.push([]);
			}
			return true;
		});
		parser.hooks.expressionMemberChain
			.for(dynamicImportTag)
			.tap(PLUGIN_NAME, (_expression, members, membersOptionals) => {
				const settings = /** @type {ImportSettings} */ (parser.currentTagData);
				const ids = getNonOptionalPart(members, membersOptionals);
				settings.references.push(ids);
				return true;
			});
		parser.hooks.callMemberChain
			.for(dynamicImportTag)
			.tap(PLUGIN_NAME, (expression, members, membersOptionals) => {
				const { arguments: args } = expression;
				const settings = /** @type {ImportSettings} */ (parser.currentTagData);
				let ids = getNonOptionalPart(members, membersOptionals);
				const directImport = members.length === 0;
				if (
					!directImport &&
					(this.options.strictThisContextOnImports || ids.length > 1)
				) {
					ids = ids.slice(0, -1);
				}
				settings.references.push(ids);
				if (args) parser.walkExpressions(args);
				return true;
			});
		parser.hooks.importCall.tap(PLUGIN_NAME, (expr, importThen) => {
			const param = parser.evaluateExpression(expr.source);

			let chunkName = null;
			let mode = /** @type {ContextMode} */ (this.options.dynamicImportMode);
			let include = null;
			let exclude = null;
			/** @type {RawReferencedExports | null} */
			let exports = null;
			/** @type {RawChunkGroupOptions} */
			const groupOptions = {};

			const {
				dynamicImportPreload,
				dynamicImportPrefetch,
				dynamicImportFetchPriority
			} = this.options;
			if (
				dynamicImportPreload !== undefined &&
				dynamicImportPreload !== false
			) {
				groupOptions.preloadOrder =
					dynamicImportPreload === true ? 0 : dynamicImportPreload;
			}
			if (
				dynamicImportPrefetch !== undefined &&
				dynamicImportPrefetch !== false
			) {
				groupOptions.prefetchOrder =
					dynamicImportPrefetch === true ? 0 : dynamicImportPrefetch;
			}
			if (
				dynamicImportFetchPriority !== undefined &&
				dynamicImportFetchPriority !== false
			) {
				groupOptions.fetchPriority = dynamicImportFetchPriority;
			}

			const { options: importOptions, errors: commentErrors } =
				parser.parseCommentOptions(/** @type {Range} */ (expr.range));

			if (commentErrors) {
				for (const e of commentErrors) {
					const { comment } = e;
					parser.state.module.addWarning(
						new CommentCompilationWarning(
							`Compilation error while processing magic comment(-s): /*${comment.value}*/: ${e.message}`,
							/** @type {DependencyLocation} */ (comment.loc)
						)
					);
				}
			}

			let phase = expr.phase;
			if (!phase && importOptions && importOptions.webpackDefer !== undefined) {
				if (typeof importOptions.webpackDefer !== "boolean") {
					parser.state.module.addWarning(
						new UnsupportedFeatureWarning(
							`\`webpackDefer\` expected a boolean, but received: ${importOptions.webpackDefer}.`,
							/** @type {DependencyLocation} */ (expr.loc)
						)
					);
				} else if (importOptions.webpackDefer) {
					phase = "defer";
				}
			}
			if (phase === "defer") {
				parser.state.module.addWarning(
					new UnsupportedFeatureWarning(
						"import.defer() is not implemented yet.",
						/** @type {DependencyLocation} */ (expr.loc)
					)
				);
			}

			if (importOptions) {
				if (importOptions.webpackIgnore !== undefined) {
					if (typeof importOptions.webpackIgnore !== "boolean") {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackIgnore\` expected a boolean, but received: ${importOptions.webpackIgnore}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					} else if (importOptions.webpackIgnore) {
						// Do not instrument `import()` if `webpackIgnore` is `true`
						return false;
					}
				}
				if (importOptions.webpackChunkName !== undefined) {
					if (typeof importOptions.webpackChunkName !== "string") {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackChunkName\` expected a string, but received: ${importOptions.webpackChunkName}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					} else {
						chunkName = importOptions.webpackChunkName;
					}
				}
				if (importOptions.webpackMode !== undefined) {
					if (typeof importOptions.webpackMode !== "string") {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackMode\` expected a string, but received: ${importOptions.webpackMode}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					} else {
						mode = /** @type {ContextMode} */ (importOptions.webpackMode);
					}
				}
				if (importOptions.webpackPrefetch !== undefined) {
					if (importOptions.webpackPrefetch === true) {
						groupOptions.prefetchOrder = 0;
					} else if (typeof importOptions.webpackPrefetch === "number") {
						groupOptions.prefetchOrder = importOptions.webpackPrefetch;
					} else {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackPrefetch\` expected true or a number, but received: ${importOptions.webpackPrefetch}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					}
				}
				if (importOptions.webpackPreload !== undefined) {
					if (importOptions.webpackPreload === true) {
						groupOptions.preloadOrder = 0;
					} else if (typeof importOptions.webpackPreload === "number") {
						groupOptions.preloadOrder = importOptions.webpackPreload;
					} else {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackPreload\` expected true or a number, but received: ${importOptions.webpackPreload}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					}
				}
				if (importOptions.webpackFetchPriority !== undefined) {
					if (
						typeof importOptions.webpackFetchPriority === "string" &&
						["high", "low", "auto"].includes(importOptions.webpackFetchPriority)
					) {
						groupOptions.fetchPriority =
							/** @type {"low" | "high" | "auto"} */
							(importOptions.webpackFetchPriority);
					} else {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackFetchPriority\` expected true or "low", "high" or "auto", but received: ${importOptions.webpackFetchPriority}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					}
				}
				if (importOptions.webpackInclude !== undefined) {
					if (
						!importOptions.webpackInclude ||
						!(importOptions.webpackInclude instanceof RegExp)
					) {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackInclude\` expected a regular expression, but received: ${importOptions.webpackInclude}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					} else {
						include = importOptions.webpackInclude;
					}
				}
				if (importOptions.webpackExclude !== undefined) {
					if (
						!importOptions.webpackExclude ||
						!(importOptions.webpackExclude instanceof RegExp)
					) {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackExclude\` expected a regular expression, but received: ${importOptions.webpackExclude}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					} else {
						exclude = importOptions.webpackExclude;
					}
				}
				if (importOptions.webpackExports !== undefined) {
					if (
						!(
							typeof importOptions.webpackExports === "string" ||
							(Array.isArray(importOptions.webpackExports) &&
								importOptions.webpackExports.every(
									(item) => typeof item === "string"
								))
						)
					) {
						parser.state.module.addWarning(
							new UnsupportedFeatureWarning(
								`\`webpackExports\` expected a string or an array of strings, but received: ${importOptions.webpackExports}.`,
								/** @type {DependencyLocation} */ (expr.loc)
							)
						);
					} else if (typeof importOptions.webpackExports === "string") {
						exports = [[importOptions.webpackExports]];
					} else {
						exports = exportsFromEnumerable(importOptions.webpackExports);
					}
				}
			}

			if (
				mode !== "lazy" &&
				mode !== "lazy-once" &&
				mode !== "eager" &&
				mode !== "weak"
			) {
				parser.state.module.addWarning(
					new UnsupportedFeatureWarning(
						`\`webpackMode\` expected 'lazy', 'lazy-once', 'eager' or 'weak', but received: ${mode}.`,
						/** @type {DependencyLocation} */ (expr.loc)
					)
				);
				mode = "lazy";
			}

			const referencedPropertiesInDestructuring =
				parser.destructuringAssignmentPropertiesFor(expr);
			const state = getState(parser);
			const referencedPropertiesInMember = state.get(expr);
			const fulfilledNamespaceObj =
				importThen && getFulfilledCallbackNamespaceObj(importThen);
			if (
				referencedPropertiesInDestructuring ||
				referencedPropertiesInMember ||
				fulfilledNamespaceObj
			) {
				if (exports) {
					parser.state.module.addWarning(
						new UnsupportedFeatureWarning(
							"You don't need `webpackExports` if the usage of dynamic import is statically analyse-able. You can safely remove the `webpackExports` magic comment.",
							/** @type {DependencyLocation} */ (expr.loc)
						)
					);
				}

				if (referencedPropertiesInDestructuring) {
					/** @type {RawReferencedExports} */
					const refsInDestructuring = [];
					traverseDestructuringAssignmentProperties(
						referencedPropertiesInDestructuring,
						(stack) => refsInDestructuring.push(stack.map((p) => p.id))
					);

					exports = refsInDestructuring;
				} else if (referencedPropertiesInMember) {
					exports = referencedPropertiesInMember;
				} else {
					/** @type {RawReferencedExports} */
					const references = [];
					state.set(expr, references);

					exports = references;
				}
			}

			if (param.isString()) {
				const attributes = getImportAttributes(expr);

				if (mode === "eager") {
					const dep = new ImportEagerDependency(
						/** @type {string} */ (param.string),
						/** @type {Range} */ (expr.range),
						exports,
						attributes
					);
					parser.state.current.addDependency(dep);
				} else if (mode === "weak") {
					const dep = new ImportWeakDependency(
						/** @type {string} */ (param.string),
						/** @type {Range} */ (expr.range),
						exports,
						attributes
					);
					parser.state.current.addDependency(dep);
				} else {
					const depBlock = new AsyncDependenciesBlock(
						{
							...groupOptions,
							name: chunkName
						},
						/** @type {DependencyLocation} */ (expr.loc),
						param.string
					);
					const dep = new ImportDependency(
						/** @type {string} */ (param.string),
						/** @type {Range} */ (expr.range),
						exports,
						attributes
					);
					dep.loc = /** @type {DependencyLocation} */ (expr.loc);
					dep.optional = Boolean(parser.scope.inTry);
					depBlock.addDependency(dep);
					parser.state.current.addBlock(depBlock);
				}
			} else {
				if (mode === "weak") {
					mode = "async-weak";
				}
				const dep = ContextDependencyHelpers.create(
					ImportContextDependency,
					/** @type {Range} */ (expr.range),
					param,
					expr,
					this.options,
					{
						chunkName,
						groupOptions,
						include,
						exclude,
						mode,
						namespaceObject:
							/** @type {BuildMeta} */
							(parser.state.module.buildMeta).strictHarmonyModule
								? "strict"
								: true,
						typePrefix: "import()",
						category: "esm",
						referencedExports: exports,
						attributes: getImportAttributes(expr)
					},
					parser
				);
				if (!dep) return;
				dep.loc = /** @type {DependencyLocation} */ (expr.loc);
				dep.optional = Boolean(parser.scope.inTry);
				parser.state.current.addDependency(dep);
			}

			if (fulfilledNamespaceObj) {
				walkImportThenFulfilledCallback(
					parser,
					expr,
					/** @type {ArrowFunctionExpression | FunctionExpression} */
					(importThen.arguments[0]),
					fulfilledNamespaceObj
				);
				parser.walkExpressions(importThen.arguments.slice(1));
			} else if (importThen) {
				parser.walkExpressions(importThen.arguments);
			}

			return true;
		});
	}
}

module.exports = ImportParserPlugin;