source: frontend/node_modules/webpack/lib/dependencies/PureExpressionDependency.js

/*
        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("../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 {
        /**
         * Creates an instance of PureExpressionDependency.
         * @param {Range} range the source range
         */
        constructor(range) {
                super();
                this.range = range;
                /** @type {Set<string> | false} */
                this.usedByExports = false;
        }

        /**
         * Get runtime condition.
         * @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;
        }

        /**
         * Updates the hash with the data contributed by this instance.
         * @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(String(this.range));
        }

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

        /**
         * Serializes this instance into the provided serializer context.
         * @param {ObjectSerializerContext} context context
         */
        serialize(context) {
                const { write } = context;
                write(this.range);
                write(this.usedByExports);
                super.serialize(context);
        }

        /**
         * Restores this instance from the provided deserializer 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
) {
        /**
         * Applies the plugin by registering its hooks on the compiler.
         * @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) {
                        // Do nothing
                } 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;