readmongo/node_modules/enhanced-resolve/lib/DescriptionFileUtils.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

const forEachBail = require("./forEachBail");

function loadDescriptionFile(
	resolver,
	directory,
	filenames,
	resolveContext,
	callback
) {
	(function findDescriptionFile() {
		forEachBail(
			filenames,
			(filename, callback) => {
				const descriptionFilePath = resolver.join(directory, filename);
				if (resolver.fileSystem.readJson) {
					resolver.fileSystem.readJson(descriptionFilePath, (err, content) => {
						if (err) {
							if (typeof err.code !== "undefined") return callback();
							return onJson(err);
						}
						onJson(null, content);
					});
				} else {
					resolver.fileSystem.readFile(descriptionFilePath, (err, content) => {
						if (err) return callback();
						let json;
						try {
							json = JSON.parse(content);
						} catch (e) {
							onJson(e);
						}
						onJson(null, json);
					});
				}

				function onJson(err, content) {
					if (err) {
						if (resolveContext.log)
							resolveContext.log(
								descriptionFilePath + " (directory description file): " + err
							);
						else
							err.message =
								descriptionFilePath + " (directory description file): " + err;
						return callback(err);
					}
					callback(null, {
						content: content,
						directory: directory,
						path: descriptionFilePath
					});
				}
			},
			(err, result) => {
				if (err) return callback(err);
				if (result) {
					return callback(null, result);
				} else {
					directory = cdUp(directory);
					if (!directory) {
						return callback();
					} else {
						return findDescriptionFile();
					}
				}
			}
		);
	})();
}

function getField(content, field) {
	if (!content) return undefined;
	if (Array.isArray(field)) {
		let current = content;
		for (let j = 0; j < field.length; j++) {
			if (current === null || typeof current !== "object") {
				current = null;
				break;
			}
			current = current[field[j]];
		}
		if (typeof current === "object") {
			return current;
		}
	} else {
		if (typeof content[field] === "object") {
			return content[field];
		}
	}
}

function cdUp(directory) {
	if (directory === "/") return null;
	const i = directory.lastIndexOf("/"),
		j = directory.lastIndexOf("\\");
	const p = i < 0 ? j : j < 0 ? i : i < j ? j : i;
	if (p < 0) return null;
	return directory.substr(0, p || 1);
}

exports.loadDescriptionFile = loadDescriptionFile;
exports.getField = getField;
exports.cdUp = cdUp;