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

"use strict";

const { UsageState } = require("../ExportsInfo");
const makeSerializable = require("../util/makeSerializable");
const { filterRuntime, runtimeToString } = require("../util/runtime");
const NullDependency = require("./NullDependency");

/** @typedef {import("webpack-sources").ReplaceSource} ReplaceSource */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Dependency").RuntimeSpec} RuntimeSpec */
/** @typedef {import("../Dependency").UpdateHashContext} UpdateHashContext */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../Module")} Module */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../ModuleGraphConnection").ConnectionState} ConnectionState */
/** @typedef {import("../javascript/JavascriptParser").Range} Range */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
/** @typedef {import("../util/Hash")} Hash */

class PureExpressionDependency extends NullDependency {
	/**
	 * @param {Range} range the source range
	 */
	constructor(range) {
		super();
		this.range = range;
		/** @type {Set | false} */
		this.usedByExports = false;
	}

	/**
	 * @param {ModuleGraph} moduleGraph module graph
	 * @param {RuntimeSpec} runtime current runtimes
	 * @returns {boolean | RuntimeSpec} runtime condition
	 */
	_getRuntimeCondition(moduleGraph, runtime) {
		const usedByExports = this.usedByExports;
		if (usedByExports !== false) {
			const selfModule =
				/** @type {Module} */
				(moduleGraph.getParentModule(this));
			const exportsInfo = moduleGraph.getExportsInfo(selfModule);
			const runtimeCondition = filterRuntime(runtime, runtime => {
				for (const exportName of usedByExports) {
					if (exportsInfo.getUsed(exportName, runtime) !== UsageState.Unused) {
						return true;
					}
				}
				return false;
			});
			return runtimeCondition;
		}
		return false;
	}

	/**
	 * Update the hash
	 * @param {Hash} hash hash to be updated
	 * @param {UpdateHashContext} context context
	 * @returns {void}
	 */
	updateHash(hash, context) {
		const runtimeCondition = this._getRuntimeCondition(
			context.chunkGraph.moduleGraph,
			context.runtime
		);
		if (runtimeCondition === true) {
			return;
		} else if (runtimeCondition === false) {
			hash.update("null");
		} else {
			hash.update(
				runtimeToString(runtimeCondition) +
					"|" +
					runtimeToString(context.runtime)
			);
		}
		hash.update(this.range + "");
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @returns {ConnectionState} how this dependency connects the module to referencing modules
	 */
	getModuleEvaluationSideEffectsState(moduleGraph) {
		return false;
	}

	/**
	 * @param {ObjectSerializerContext} context context
	 */
	serialize(context) {
		const { write } = context;
		write(this.range);
		write(this.usedByExports);
		super.serialize(context);
	}

	/**
	 * @param {ObjectDeserializerContext} context context
	 */
	deserialize(context) {
		const { read } = context;
		this.range = read();
		this.usedByExports = read();
		super.deserialize(context);
	}
}

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

PureExpressionDependency.Template = class PureExpressionDependencyTemplate extends (
	NullDependency.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,
		{ chunkGraph, moduleGraph, runtime, runtimeTemplate, runtimeRequirements }
	) {
		const dep = /** @type {PureExpressionDependency} */ (dependency);
		const runtimeCondition = dep._getRuntimeCondition(moduleGraph, runtime);
		if (runtimeCondition === true) {
			return;
		} else if (runtimeCondition === false) {
			source.insert(
				dep.range[0],
				`(/* unused pure expression or super */ null && (`
			);
			source.insert(dep.range[1], "))");
		} else {
			const condition = runtimeTemplate.runtimeConditionExpression({
				chunkGraph,
				runtime,
				runtimeCondition,
				runtimeRequirements
			});
			source.insert(
				dep.range[0],
				`(/* runtime-dependent pure expression or super */ ${condition} ? (`
			);
			source.insert(dep.range[1], ") : null)");
		}
	}
};

module.exports = PureExpressionDependency;