webpack/lib/css/CssMergeStyleSheetsRuntimeModule.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 Natsu @xiaoxiaojx
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");

/** @typedef {import("../Chunk")} Chunk */

class CssMergeStyleSheetsRuntimeModule extends RuntimeModule {
	constructor() {
		super("css merge stylesheets");
	}

	/**
	 * @returns {string | null} runtime code
	 */
	generate() {
		const { runtimeTemplate } = /** @type {import("../Compilation")} */ (
			this.compilation
		);

		return Template.asString([
			`${RuntimeGlobals.cssMergeStyleSheets} = ${runtimeTemplate.basicFunction(
				"sheets",
				[
					"var sheetsArray = Array.isArray(sheets) ? sheets : [sheets];",
					"var cssTexts = [];",
					"for (var i = 0; i < sheetsArray.length; i++) {",
					Template.indent([
						"var s = sheetsArray[i];",
						"if (!s) continue;",
						"if (typeof s === 'string') {",
						Template.indent("cssTexts.push(s);"),
						"} else if (s.cssRules) {",
						Template.indent([
							"var rules = s.cssRules;",
							"for (var j = 0; j < rules.length; j++) {",
							Template.indent("cssTexts.push(rules[j].cssText);"),
							"}"
						]),
						"}"
					]),
					"}",
					"return cssTexts.join('');"
				]
			)};`
		]);
	}
}

module.exports = CssMergeStyleSheetsRuntimeModule;