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("../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 */

/**
 * Defines the get exports from data fn callback.
 * @callback GetExportsFromDataFn
 * @param {JsonValue} data raw json data
 * @param {number=} curDepth current depth
 * @returns {ExportSpec[] | null} export spec or nothing
 */

/**
 * Gets exports with depth.
 * @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(
							/** @type {JsonValue} */
							(data[key]),
							curDepth + 1
						) || undefined
				});
			}

			return exports;
		}

		return null;
	};

class JsonExportsDependency extends NullDependency {
	/**
	 * Creates an instance of JsonExportsDependency.
	 * @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
		};
	}

	/**
	 * 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) {
		this.data.updateHash(hash);
	}

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

	/**
	 * Restores this instance from the provided deserializer 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;