--- /dev/null
+/**
+ * @fileoverview Utility to get information about the execution environment.
+ * @author Kai Cataldo
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const path = require("path");
+const spawn = require("cross-spawn");
+const { isEmpty } = require("lodash");
+const log = require("../shared/logging");
+const packageJson = require("../../package.json");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Generates and returns execution environment information.
+ * @returns {string} A string that contains execution environment information.
+ */
+function environment() {
+ const cache = new Map();
+
+ /**
+ * Checks if a path is a child of a directory.
+ * @param {string} parentPath The parent path to check.
+ * @param {string} childPath The path to check.
+ * @returns {boolean} Whether or not the given path is a child of a directory.
+ */
+ function isChildOfDirectory(parentPath, childPath) {
+ return !path.relative(parentPath, childPath).startsWith("..");
+ }
+
+ /**
+ * Synchronously executes a shell command and formats the result.
+ * @param {string} cmd The command to execute.
+ * @param {Array} args The arguments to be executed with the command.
+ * @returns {string} The version returned by the command.
+ */
+ function execCommand(cmd, args) {
+ const key = [cmd, ...args].join(" ");
+
+ if (cache.has(key)) {
+ return cache.get(key);
+ }
+
+ const process = spawn.sync(cmd, args, { encoding: "utf8" });
+
+ if (process.error) {
+ throw process.error;
+ }
+
+ const result = process.stdout.trim();
+
+ cache.set(key, result);
+ return result;
+ }
+
+ /**
+ * Normalizes a version number.
+ * @param {string} versionStr The string to normalize.
+ * @returns {string} The normalized version number.
+ */
+ function normalizeVersionStr(versionStr) {
+ return versionStr.startsWith("v") ? versionStr : `v${versionStr}`;
+ }
+
+ /**
+ * Gets bin version.
+ * @param {string} bin The bin to check.
+ * @returns {string} The normalized version returned by the command.
+ */
+ function getBinVersion(bin) {
+ const binArgs = ["--version"];
+
+ try {
+ return normalizeVersionStr(execCommand(bin, binArgs));
+ } catch (e) {
+ log.error(`Error finding ${bin} version running the command \`${bin} ${binArgs.join(" ")}\``);
+ throw e;
+ }
+ }
+
+ /**
+ * Gets installed npm package version.
+ * @param {string} pkg The package to check.
+ * @param {boolean} global Whether to check globally or not.
+ * @returns {string} The normalized version returned by the command.
+ */
+ function getNpmPackageVersion(pkg, { global = false } = {}) {
+ const npmBinArgs = ["bin", "-g"];
+ const npmLsArgs = ["ls", "--depth=0", "--json", "eslint"];
+
+ if (global) {
+ npmLsArgs.push("-g");
+ }
+
+ try {
+ const parsedStdout = JSON.parse(execCommand("npm", npmLsArgs));
+
+ /*
+ * Checking globally returns an empty JSON object, while local checks
+ * include the name and version of the local project.
+ */
+ if (isEmpty(parsedStdout) || !(parsedStdout.dependencies && parsedStdout.dependencies.eslint)) {
+ return "Not found";
+ }
+
+ const [, processBinPath] = process.argv;
+ let npmBinPath;
+
+ try {
+ npmBinPath = execCommand("npm", npmBinArgs);
+ } catch (e) {
+ log.error(`Error finding npm binary path when running command \`npm ${npmBinArgs.join(" ")}\``);
+ throw e;
+ }
+
+ const isGlobal = isChildOfDirectory(npmBinPath, processBinPath);
+ let pkgVersion = parsedStdout.dependencies.eslint.version;
+
+ if ((global && isGlobal) || (!global && !isGlobal)) {
+ pkgVersion += " (Currently used)";
+ }
+
+ return normalizeVersionStr(pkgVersion);
+ } catch (e) {
+ log.error(`Error finding ${pkg} version running the command \`npm ${npmLsArgs.join(" ")}\``);
+ throw e;
+ }
+ }
+
+ return [
+ "Environment Info:",
+ "",
+ `Node version: ${getBinVersion("node")}`,
+ `npm version: ${getBinVersion("npm")}`,
+ `Local ESLint version: ${getNpmPackageVersion("eslint", { global: false })}`,
+ `Global ESLint version: ${getNpmPackageVersion("eslint", { global: true })}`
+ ].join("\n");
+}
+
+/**
+ * Returns version of currently executing ESLint.
+ * @returns {string} The version from the currently executing ESLint's package.json.
+ */
+function version() {
+ return `v${packageJson.version}`;
+}
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+module.exports = {
+ environment,
+ version
+};