webpack/lib/ConditionalInitFragment.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 { ConcatSource, PrefixSource } = require("webpack-sources");
const InitFragment = require("./InitFragment");
const Template = require("./Template");
const { mergeRuntime } = require("./util/runtime");

/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("./Generator").GenerateContext} GenerateContext */
/** @typedef {import("./util/runtime").RuntimeSpec} RuntimeSpec */

/**
 * Returns wrapped source.
 * @param {string} condition condition
 * @param {string | Source} source source
 * @returns {string | Source} wrapped source
 */
const wrapInCondition = (condition, source) => {
	if (typeof source === "string") {
		return Template.asString([
			`if (${condition}) {`,
			Template.indent(source),
			"}",
			""
		]);
	}
	return new ConcatSource(
		`if (${condition}) {\n`,
		new PrefixSource("\t", source),
		"}\n"
	);
};

/**
 * Represents ConditionalInitFragment.
 * @extends {InitFragment<GenerateContext>}
 */
class ConditionalInitFragment extends InitFragment {
	/**
	 * Creates an instance of ConditionalInitFragment.
	 * @param {string | Source | undefined} content the source code that will be included as initialization code
	 * @param {number} stage category of initialization code (contribute to order)
	 * @param {number} position position in the category (contribute to order)
	 * @param {string | undefined} key unique key to avoid emitting the same initialization code twice
	 * @param {RuntimeSpec | boolean} runtimeCondition in which runtime this fragment should be executed
	 * @param {string | Source=} endContent the source code that will be included at the end of the module
	 */
	constructor(
		content,
		stage,
		position,
		key,
		runtimeCondition = true,
		endContent = undefined
	) {
		super(content, stage, position, key, endContent);
		this.runtimeCondition = runtimeCondition;
	}

	/**
	 * Returns the source code that will be included as initialization code.
	 * @param {GenerateContext} context context
	 * @returns {string | Source | undefined} the source code that will be included as initialization code
	 */
	getContent(context) {
		if (this.runtimeCondition === false || !this.content) return "";
		if (this.runtimeCondition === true) return this.content;
		const expr = context.runtimeTemplate.runtimeConditionExpression({
			chunkGraph: context.chunkGraph,
			runtimeRequirements: context.runtimeRequirements,
			runtime: context.runtime,
			runtimeCondition: this.runtimeCondition
		});
		if (expr === "true") return this.content;
		return wrapInCondition(expr, this.content);
	}

	/**
	 * Returns the source code that will be included at the end of the module.
	 * @param {GenerateContext} context context
	 * @returns {string | Source | undefined} the source code that will be included at the end of the module
	 */
	getEndContent(context) {
		if (this.runtimeCondition === false || !this.endContent) return "";
		if (this.runtimeCondition === true) return this.endContent;
		const expr = context.runtimeTemplate.runtimeConditionExpression({
			chunkGraph: context.chunkGraph,
			runtimeRequirements: context.runtimeRequirements,
			runtime: context.runtime,
			runtimeCondition: this.runtimeCondition
		});
		if (expr === "true") return this.endContent;
		return wrapInCondition(expr, this.endContent);
	}

	/**
	 * Returns merged fragment.
	 * @param {ConditionalInitFragment} other fragment to merge with
	 * @returns {ConditionalInitFragment} merged fragment
	 */
	merge(other) {
		if (this.runtimeCondition === true) return this;
		if (other.runtimeCondition === true) return other;
		if (this.runtimeCondition === false) return other;
		if (other.runtimeCondition === false) return this;
		const runtimeCondition = mergeRuntime(
			this.runtimeCondition,
			other.runtimeCondition
		);
		return new ConditionalInitFragment(
			this.content,
			this.stage,
			this.position,
			this.key,
			runtimeCondition,
			this.endContent
		);
	}
}

module.exports = ConditionalInitFragment;