webpack/lib/CompatibilityPlugin.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 {
	JAVASCRIPT_MODULE_TYPE_AUTO,
	JAVASCRIPT_MODULE_TYPE_DYNAMIC,
	JAVASCRIPT_MODULE_TYPE_ESM
} = require("./ModuleTypeConstants");
const RuntimeGlobals = require("./RuntimeGlobals");
const ConstDependency = require("./dependencies/ConstDependency");

/** @typedef {import("estree").CallExpression} CallExpression */
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./Dependency").DependencyLocation} DependencyLocation */
/** @typedef {import("./javascript/JavascriptParser")} JavascriptParser */
/** @typedef {import("./javascript/JavascriptParser").Range} Range */

const nestedWebpackIdentifierTag = Symbol("nested webpack identifier");
const PLUGIN_NAME = "CompatibilityPlugin";

class CompatibilityPlugin {
	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap(
			PLUGIN_NAME,
			(compilation, { normalModuleFactory }) => {
				compilation.dependencyTemplates.set(
					ConstDependency,
					new ConstDependency.Template()
				);

				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_AUTO)
					.tap(PLUGIN_NAME, (parser, parserOptions) => {
						if (
							parserOptions.browserify !== undefined &&
							!parserOptions.browserify
						)
							return;

						parser.hooks.call.for("require").tap(
							PLUGIN_NAME,
							/**
							 * @param {CallExpression} expr call expression
							 * @returns {boolean | void} true when need to handle
							 */
							expr => {
								// support for browserify style require delegator: "require(o, !0)"
								if (expr.arguments.length !== 2) return;
								const second = parser.evaluateExpression(expr.arguments[1]);
								if (!second.isBoolean()) return;
								if (second.asBool() !== true) return;
								const dep = new ConstDependency(
									"require",
									/** @type {Range} */ (expr.callee.range)
								);
								dep.loc = /** @type {DependencyLocation} */ (expr.loc);
								if (parser.state.current.dependencies.length > 0) {
									const last =
										parser.state.current.dependencies[
											parser.state.current.dependencies.length - 1
										];
									if (
										last.critical &&
										last.options &&
										last.options.request === "." &&
										last.userRequest === "." &&
										last.options.recursive
									)
										parser.state.current.dependencies.pop();
								}
								parser.state.module.addPresentationalDependency(dep);
								return true;
							}
						);
					});

				/**
				 * @param {JavascriptParser} parser the parser
				 * @returns {void}
				 */
				const handler = parser => {
					// Handle nested requires
					parser.hooks.preStatement.tap(PLUGIN_NAME, statement => {
						if (
							statement.type === "FunctionDeclaration" &&
							statement.id &&
							statement.id.name === RuntimeGlobals.require
						) {
							const newName = `__nested_webpack_require_${
								/** @type {Range} */ (statement.range)[0]
							}__`;
							parser.tagVariable(
								statement.id.name,
								nestedWebpackIdentifierTag,
								{
									name: newName,
									declaration: {
										updated: false,
										loc: statement.id.loc,
										range: statement.id.range
									}
								}
							);
							return true;
						}
					});
					parser.hooks.pattern
						.for(RuntimeGlobals.require)
						.tap(PLUGIN_NAME, pattern => {
							const newName = `__nested_webpack_require_${
								/** @type {Range} */ (pattern.range)[0]
							}__`;
							parser.tagVariable(pattern.name, nestedWebpackIdentifierTag, {
								name: newName,
								declaration: {
									updated: false,
									loc: pattern.loc,
									range: pattern.range
								}
							});
							return true;
						});
					parser.hooks.pattern
						.for(RuntimeGlobals.exports)
						.tap(PLUGIN_NAME, pattern => {
							parser.tagVariable(pattern.name, nestedWebpackIdentifierTag, {
								name: "__nested_webpack_exports__",
								declaration: {
									updated: false,
									loc: pattern.loc,
									range: pattern.range
								}
							});
							return true;
						});
					parser.hooks.expression
						.for(nestedWebpackIdentifierTag)
						.tap(PLUGIN_NAME, expr => {
							const { name, declaration } = parser.currentTagData;
							if (!declaration.updated) {
								const dep = new ConstDependency(name, declaration.range);
								dep.loc = declaration.loc;
								parser.state.module.addPresentationalDependency(dep);
								declaration.updated = true;
							}
							const dep = new ConstDependency(
								name,
								/** @type {Range} */ (expr.range)
							);
							dep.loc = /** @type {DependencyLocation} */ (expr.loc);
							parser.state.module.addPresentationalDependency(dep);
							return true;
						});

					// Handle hashbang
					parser.hooks.program.tap(PLUGIN_NAME, (program, comments) => {
						if (comments.length === 0) return;
						const c = comments[0];
						if (c.type === "Line" && /** @type {Range} */ (c.range)[0] === 0) {
							if (parser.state.source.slice(0, 2).toString() !== "#!") return;
							// this is a hashbang comment
							const dep = new ConstDependency("//", 0);
							dep.loc = /** @type {DependencyLocation} */ (c.loc);
							parser.state.module.addPresentationalDependency(dep);
						}
					});
				};

				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_AUTO)
					.tap(PLUGIN_NAME, handler);
				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_DYNAMIC)
					.tap(PLUGIN_NAME, handler);
				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_ESM)
					.tap(PLUGIN_NAME, handler);
			}
		);
	}
}
module.exports = CompatibilityPlugin;