webpack/lib/dependencies/BuildTimeConstDependency.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 Alexander Akait @alexander-akait
*/

"use strict";

const makeSerializable = require("../util/makeSerializable");
const ConstDependency = require("./ConstDependency");
const NullDependency = require("./NullDependency");

/** @import { ReplaceSource } from "webpack-sources" */
/** @import Dependency, { UpdateHashContext } from "../Dependency" */
/** @import { DependencyTemplateContext } from "../DependencyTemplate" */
/** @import { Range } from "../javascript/JavascriptParser" */
/**
 * @import {
 * 	ObjectDeserializerContext,
 * 	ObjectSerializerContext
 * } from "../serialization/ObjectMiddleware"
 */
/** @import Hash from "../util/Hash" */

/**
 * A constant replacement whose source is only valid in emitted output (e.g.
 * native `import.meta`), with a separate expression for build-time execution.
 */
class BuildTimeConstDependency extends ConstDependency {
	/**
	 * Creates an instance of BuildTimeConstDependency.
	 * @param {string} expression the expression
	 * @param {string} buildTimeExpression the expression for build-time execution
	 * @param {Range} range the source range
	 * @param {(string[] | null)=} runtimeRequirements runtime requirements
	 */
	constructor(expression, buildTimeExpression, range, runtimeRequirements) {
		super(expression, range, runtimeRequirements);
		/** @type {string} */
		this.buildTimeExpression = buildTimeExpression;
	}

	/**
	 * 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) {
		super.updateHash(hash, context);
		hash.update(this.buildTimeExpression);
	}

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

	/**
	 * Restores this instance from the provided deserializer context.
	 * @param {ObjectDeserializerContext} context context
	 */
	deserialize(context) {
		this.buildTimeExpression = context.read();
		super.deserialize(context.rest);
	}
}

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

BuildTimeConstDependency.Template = class BuildTimeConstDependencyTemplate 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, templateContext) {
		const dep = /** @type {BuildTimeConstDependency} */ (dependency);
		if (dep.runtimeRequirements) {
			for (const req of dep.runtimeRequirements) {
				templateContext.runtimeRequirements.add(req);
			}
		}
		const expression = templateContext.chunkGraph.buildTimeExecution
			? dep.buildTimeExpression
			: dep.expression;
		const range = /** @type {Range} */ (dep.range);
		source.replace(range[0], range[1] - 1, expression);
	}
};

module.exports = BuildTimeConstDependency;