webpack/lib/dependencies/HarmonyEvaluatedImportSpecifierDependency.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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 Ivan Kopeykin @vankop
*/

"use strict";

const makeSerializable = require("../util/makeSerializable");
const HarmonyImportSpecifierDependency = require("./HarmonyImportSpecifierDependency");

/** @typedef {import("webpack-sources").ReplaceSource} ReplaceSource */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */

/**
 * Dependency for static evaluating import specifier. e.g.
 * @example
 * import a from "a";
 * "x" in a;
 * a.x !== undefined; // if x value statically analyzable
 */
class HarmonyEvaluatedImportSpecifierDependency extends HarmonyImportSpecifierDependency {
	constructor(request, sourceOrder, ids, name, range, assertions, operator) {
		super(request, sourceOrder, ids, name, range, false, assertions);
		this.operator = operator;
	}

	get type() {
		return `evaluated X ${this.operator} harmony import specifier`;
	}

	serialize(context) {
		super.serialize(context);
		const { write } = context;
		write(this.operator);
	}

	deserialize(context) {
		super.deserialize(context);
		const { read } = context;
		this.operator = read();
	}
}

makeSerializable(
	HarmonyEvaluatedImportSpecifierDependency,
	"webpack/lib/dependencies/HarmonyEvaluatedImportSpecifierDependency"
);

HarmonyEvaluatedImportSpecifierDependency.Template = class HarmonyEvaluatedImportSpecifierDependencyTemplate extends (
	HarmonyImportSpecifierDependency.Template
) {
	/**
	 * @param {Dependency} dependency the dependency for which the template should be applied
	 * @param {ReplaceSource} source the current replace source which can be modified
	 * @param {DependencyTemplateContext} templateContext the context object
	 * @returns {void}
	 */
	apply(dependency, source, templateContext) {
		const dep = /** @type {HarmonyEvaluatedImportSpecifierDependency} */ (
			dependency
		);
		const { module, moduleGraph, runtime } = templateContext;
		const connection = moduleGraph.getConnection(dep);
		// Skip rendering depending when dependency is conditional
		if (connection && !connection.isTargetActive(runtime)) return;

		const exportsInfo = moduleGraph.getExportsInfo(connection.module);
		const ids = dep.getIds(moduleGraph);

		let value;

		const exportsType = connection.module.getExportsType(
			moduleGraph,
			module.buildMeta.strictHarmonyModule
		);
		switch (exportsType) {
			case "default-with-named": {
				if (ids[0] === "default") {
					value =
						ids.length === 1 || exportsInfo.isExportProvided(ids.slice(1));
				} else {
					value = exportsInfo.isExportProvided(ids);
				}
				break;
			}
			case "namespace": {
				if (ids[0] === "__esModule") {
					value = ids.length === 1 || undefined;
				} else {
					value = exportsInfo.isExportProvided(ids);
				}
				break;
			}
			case "dynamic": {
				if (ids[0] !== "default") {
					value = exportsInfo.isExportProvided(ids);
				}
				break;
			}
			// default-only could lead to runtime error, when default value is primitive
		}

		if (typeof value === "boolean") {
			source.replace(dep.range[0], dep.range[1] - 1, ` ${value}`);
		} else {
			const usedName = exportsInfo.getUsedName(ids, runtime);

			const code = this._getCodeForIds(
				dep,
				source,
				templateContext,
				ids.slice(0, -1)
			);
			source.replace(
				dep.range[0],
				dep.range[1] - 1,
				`${
					usedName ? JSON.stringify(usedName[usedName.length - 1]) : '""'
				} in ${code}`
			);
		}
	}
};

module.exports = HarmonyEvaluatedImportSpecifierDependency;