routie dev init since i didn't adhere to any proper guidance up until now

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

@@ -0,0 +1,221 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const forEachBail = require("./forEachBail");
+
+/** @typedef {import("./Resolver")} Resolver */
+/** @typedef {import("./Resolver").JsonObject} JsonObject */
+/** @typedef {import("./Resolver").JsonValue} JsonValue */
+/** @typedef {import("./Resolver").ResolveContext} ResolveContext */
+/** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
+
+/**
+ * @typedef {object} DescriptionFileInfo
+ * @property {JsonObject=} content content
+ * @property {string} path path
+ * @property {string} directory directory
+ */
+
+/**
+ * @callback ErrorFirstCallback
+ * @param {Error | null=} error
+ * @param {DescriptionFileInfo=} result
+ */
+
+/**
+ * @typedef {object} Result
+ * @property {string} path path to description file
+ * @property {string} directory directory of description file
+ * @property {JsonObject} content content of description file
+ */
+
+const CHAR_SLASH = 47;
+const CHAR_BACKSLASH = 92;
+
+/**
+ * Walk up one directory. Called once per package-root candidate and once per
+ * `described-resolve` (to find the enclosing description file), so it's on
+ * the resolver's hot path.
+ *
+ * Previous implementation called `lastIndexOf("/")` and `lastIndexOf("\\")`
+ * separately and then picked the larger. For any non-trivial directory
+ * string on POSIX, `lastIndexOf("\\")` scans the full string just to return
+ * -1. A single reverse char-code scan does the same work in one pass.
+ *
+ * Any single-character directory is treated as a root — `directory.length
+ * <= 1` collapses the `"/"`, `"\\"` and `""` branches into one compare.
+ * Without the `"\\"` case, `cdUp("\\")` (reached from a UNC root or a DOS
+ * device path like `\\?\…`) would return itself via `slice(0, i || 1)`
+ * and trap `loadDescriptionFile` in an infinite loop. Once single-char
+ * roots are filtered up front, the reverse scan always produces a
+ * strictly shorter string.
+ * @param {string} directory directory
+ * @returns {string | null} parent directory or null
+ */
+function cdUp(directory) {
+	if (directory.length <= 1) return null;
+	for (let i = directory.length - 1; i >= 0; i--) {
+		const code = directory.charCodeAt(i);
+		if (code === CHAR_SLASH || code === CHAR_BACKSLASH) {
+			return directory.slice(0, i || 1);
+		}
+	}
+	return null;
+}
+
+/**
+ * @param {Resolver} resolver resolver
+ * @param {string} directory directory
+ * @param {string[]} filenames filenames
+ * @param {DescriptionFileInfo | undefined} oldInfo oldInfo
+ * @param {ResolveContext} resolveContext resolveContext
+ * @param {ErrorFirstCallback} callback callback
+ */
+function loadDescriptionFile(
+	resolver,
+	directory,
+	filenames,
+	oldInfo,
+	resolveContext,
+	callback,
+) {
+	(function findDescriptionFile() {
+		if (oldInfo && oldInfo.directory === directory) {
+			// We already have info for this directory and can reuse it
+			return callback(null, oldInfo);
+		}
+		forEachBail(
+			filenames,
+			/**
+			 * @param {string} filename filename
+			 * @param {(err?: null | Error, result?: null | Result) => void} callback callback
+			 * @returns {void}
+			 */
+			(filename, callback) => {
+				const descriptionFilePath = resolver.join(directory, filename);
+
+				/**
+				 * @param {(null | Error)=} err error
+				 * @param {JsonObject=} resolvedContent content
+				 * @returns {void}
+				 */
+				function onJson(err, resolvedContent) {
+					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: /** @type {JsonObject} */ (resolvedContent),
+						directory,
+						path: descriptionFilePath,
+					});
+				}
+
+				if (resolver.fileSystem.readJson) {
+					resolver.fileSystem.readJson(descriptionFilePath, (err, content) => {
+						if (err) {
+							if (
+								typeof (/** @type {NodeJS.ErrnoException} */ (err).code) !==
+								"undefined"
+							) {
+								if (resolveContext.missingDependencies) {
+									resolveContext.missingDependencies.add(descriptionFilePath);
+								}
+								return callback();
+							}
+							if (resolveContext.fileDependencies) {
+								resolveContext.fileDependencies.add(descriptionFilePath);
+							}
+							return onJson(err);
+						}
+						if (resolveContext.fileDependencies) {
+							resolveContext.fileDependencies.add(descriptionFilePath);
+						}
+						onJson(null, content);
+					});
+				} else {
+					resolver.fileSystem.readFile(descriptionFilePath, (err, content) => {
+						if (err) {
+							if (resolveContext.missingDependencies) {
+								resolveContext.missingDependencies.add(descriptionFilePath);
+							}
+							return callback();
+						}
+						if (resolveContext.fileDependencies) {
+							resolveContext.fileDependencies.add(descriptionFilePath);
+						}
+
+						/** @type {JsonObject | undefined} */
+						let json;
+
+						if (content) {
+							try {
+								json = JSON.parse(content.toString());
+							} catch (/** @type {unknown} */ err_) {
+								return onJson(/** @type {Error} */ (err_));
+							}
+						} else {
+							return onJson(new Error("No content in file"));
+						}
+
+						onJson(null, json);
+					});
+				}
+			},
+			/**
+			 * @param {(null | Error)=} err error
+			 * @param {(null | Result)=} result result
+			 * @returns {void}
+			 */
+			(err, result) => {
+				if (err) return callback(err);
+				if (result) return callback(null, result);
+				const dir = cdUp(directory);
+				if (!dir) {
+					return callback();
+				}
+				directory = dir;
+				return findDescriptionFile();
+			},
+		);
+	})();
+}
+
+/**
+ * @param {JsonObject} content content
+ * @param {string | string[]} field field
+ * @returns {JsonValue | undefined} field data
+ */
+function getField(content, field) {
+	if (!content) return undefined;
+	if (Array.isArray(field)) {
+		/** @type {JsonValue} */
+		let current = content;
+		for (let j = 0; j < field.length; j++) {
+			if (current === null || typeof current !== "object") {
+				current = null;
+				break;
+			}
+			current = /** @type {JsonValue} */ (
+				/** @type {JsonObject} */
+				(current)[field[j]]
+			);
+		}
+		return current;
+	}
+	return content[field];
+}
+
+module.exports.cdUp = cdUp;
+module.exports.getField = getField;
+module.exports.loadDescriptionFile = loadDescriptionFile;