webpack/lib/ConditionalInitFragment.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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 */

const wrapInCondition = (condition, source) => {
	if (typeof source === "string") {
		return Template.asString([
			`if (${condition}) {`,
			Template.indent(source),
			"}",
			""
		]);
	} else {
		return new ConcatSource(
			`if (${condition}) {\n`,
			new PrefixSource("\t", source),
			"}\n"
		);
	}
};

/**
 * @typedef {GenerateContext} Context
 */
class ConditionalInitFragment extends InitFragment {
	/**
	 * @param {string|Source} 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} 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
	) {
		super(content, stage, position, key, endContent);
		this.runtimeCondition = runtimeCondition;
	}

	/**
	 * @param {Context} context context
	 * @returns {string|Source} 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);
	}

	/**
	 * @param {Context} context context
	 * @returns {string|Source=} 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);
	}

	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;