webpack/lib/dependencies/JsonExportsDependency.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 makeSerializable = require("../util/makeSerializable");
const NullDependency = require("./NullDependency");

/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Dependency").ExportSpec} ExportSpec */
/** @typedef {import("../Dependency").ExportsSpec} ExportsSpec */
/** @typedef {import("../Dependency").UpdateHashContext} UpdateHashContext */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../json/JsonData")} JsonData */
/** @typedef {import("../json/JsonData").JsonValue} JsonValue */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
/** @typedef {import("../util/Hash")} Hash */

/**
 * @callback GetExportsFromDataFn
 * @param {JsonValue} data raw json data
 * @param {number=} curDepth current depth
 * @returns {ExportSpec[] | null} export spec or nothing
 */

/**
 * @param {number} exportsDepth exportsDepth
 * @returns {GetExportsFromDataFn} value
 */
const getExportsWithDepth = exportsDepth =>
	/** @type {GetExportsFromDataFn} */
	function getExportsFromData(data, curDepth = 1) {
		if (curDepth > exportsDepth) {
			return null;
		}

		if (data && typeof data === "object") {
			if (Array.isArray(data)) {
				return data.length < 100
					? data.map((item, idx) => ({
							name: `${idx}`,
							canMangle: true,
							exports: getExportsFromData(item, curDepth + 1) || undefined
						}))
					: null;
			}

			/** @type {ExportSpec[]} */
			const exports = [];

			for (const key of Object.keys(data)) {
				exports.push({
					name: key,
					canMangle: true,
					exports: getExportsFromData(data[key], curDepth + 1) || undefined
				});
			}

			return exports;
		}

		return null;
	};

class JsonExportsDependency extends NullDependency {
	/**
	 * @param {JsonData} data json data
	 * @param {number} exportsDepth the depth of json exports to analyze
	 */
	constructor(data, exportsDepth) {
		super();
		this.data = data;
		this.exportsDepth = exportsDepth;
	}

	get type() {
		return "json exports";
	}

	/**
	 * Returns the exported names
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {ExportsSpec | undefined} export names
	 */
	getExports(moduleGraph) {
		return {
			exports: getExportsWithDepth(this.exportsDepth)(
				this.data && /** @type {JsonValue} */ (this.data.get())
			),
			dependencies: undefined
		};
	}

	/**
	 * Update the hash
	 * @param {Hash} hash hash to be updated
	 * @param {UpdateHashContext} context context
	 * @returns {void}
	 */
	updateHash(hash, context) {
		this.data.updateHash(hash);
	}

	/**
	 * @param {ObjectSerializerContext} context context
	 */
	serialize(context) {
		const { write } = context;
		write(this.data);
		write(this.exportsDepth);
		super.serialize(context);
	}

	/**
	 * @param {ObjectDeserializerContext} context context
	 */
	deserialize(context) {
		const { read } = context;
		this.data = read();
		this.exportsDepth = read();
		super.deserialize(context);
	}
}

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

module.exports = JsonExportsDependency;