ESLint updates and linting cleanup

packages/less/.eslintrc.js

@@ -0,0 +1,50 @@
+module.exports = {
+    'parser': '@typescript-eslint/parser',
+    'extends': 'eslint:recommended',
+    'parserOptions': {
+        'ecmaVersion': 2018,
+        'sourceType': 'module'
+    },
+    'plugins': ['@typescript-eslint'],
+    'env': {
+        'browser': true,
+        'node': true,
+        'mocha': true
+    },
+    'globals': {},
+    'rules': {
+        indent: ['error', 4, {
+            SwitchCase: 1
+        }],
+        'no-empty': ['error', { 'allowEmptyCatch': true }],
+        quotes: ['error', 'single', {
+            avoidEscape: true
+        }],
+        /**
+         * The codebase uses some while(true) statements.
+         * Refactor to remove this rule.
+         */
+        'no-constant-condition': 0,
+        /**
+         * Less combines assignments with conditionals sometimes
+         */
+        'no-cond-assign': 0,
+        /**
+         * @todo - remove when some kind of code style (XO?) is added
+         */
+        'no-multiple-empty-lines': 'error'
+    },
+    'overrides': [
+        {
+            files: ['*.ts'],
+            extends: ['plugin:@typescript-eslint/recommended'],
+            rules: {
+                /**
+                 * Suppress until Less has better-defined types
+                 * @see https://github.com/less/less.js/discussions/3786
+                 */
+                '@typescript-eslint/no-explicit-any': 0
+            }
+        }
+    ]
+}

packages/less/Gruntfile.js

@@ -283,7 +283,7 @@ module.exports = function(grunt) {
                 "!test/less/errors/plugin/plugin-error.js"
             ],
             options: {
-                configFile: ".eslintrc.json",
+                configFile: ".eslintrc.js",
                 fix: true
             }
         },

packages/less/package.json

@@ -37,6 +37,7 @@
 	"scripts": {
 		"test": "grunt test",
 		"grunt": "grunt",
+		"lint": "eslint '**/*.{ts,js}'",
 		"build": "npm-run-all clean compile",
 		"clean": "shx rm -rf ./lib tsconfig.tsbuildinfo",
 		"compile": "tsc -p tsconfig.json",

packages/less/src/less-browser/bootstrap.js

@@ -3,8 +3,6 @@
  * used in the browser distributed version of less
  * to kick-start less using the browser api
  */
-/* global window, document */
-
 import defaultOptions from '../less/default-options';
 import addDefaultOptions from './add-default-options';
 import root from './index';
@@ -13,7 +11,7 @@ const options = defaultOptions();
 
 if (window.less) {
     for (const key in window.less) {
-        if (window.less.hasOwnProperty(key)) {
+        if (Object.prototype.hasOwnProperty.call(window.less, key)) {
             options[key] = window.less[key];
         }
     }

packages/less/src/less-browser/cache.js

@@ -29,7 +29,7 @@ export default (window, options, logger) => {
             let vars      = cache && cache.getItem(`${path}:vars`);
 
             modifyVars = modifyVars || {};
-            vars = vars || "{}"; // if not set, treat as the JSON representation of an empty object
+            vars = vars || '{}'; // if not set, treat as the JSON representation of an empty object
 
             if (timestamp && webInfo.lastModified &&
                 (new Date(webInfo.lastModified).valueOf() ===

packages/less/src/less-browser/error-reporting.js

@@ -11,7 +11,7 @@ export default (window, less, options) => {
         let content;
         const errors = [];
         const filename = e.filename || rootHref;
-        const filenameNoPath = filename.match(/([^\/]+(\?.*)?)$/)[1];
+        const filenameNoPath = filename.match(/([^/]+(\?.*)?)$/)[1];
 
         elem.id        = id;
         elem.className = 'less-error-message';
@@ -113,7 +113,7 @@ export default (window, less, options) => {
         }
     }
 
-    function removeErrorConsole(path) {
+    function removeErrorConsole() {
         // no action
     }
 

packages/less/src/less-browser/file-manager.js

@@ -1,5 +1,3 @@
-/* global window, XMLHttpRequest */
-
 import AbstractFileManager from '../less/environment/abstract-file-manager.js';
 
 let options;
@@ -66,7 +64,7 @@ FileManager.prototype = Object.assign(new AbstractFileManager(), {
         fileCache = {};
     },
 
-    loadFile(filename, currentDirectory, options, environment) {
+    loadFile(filename, currentDirectory, options) {
         // TODO: Add prefix support like less-node?
         // What about multiple paths?
 

packages/less/src/less-browser/index.js

@@ -39,7 +39,7 @@ export default (window, options) => {
     function clone(obj) {
         const cloned = {};
         for (const prop in obj) {
-            if (obj.hasOwnProperty(prop)) {
+            if (Object.prototype.hasOwnProperty.call(obj, prop)) {
                 cloned[prop] = obj[prop];
             }
         }
@@ -159,6 +159,10 @@ export default (window, options) => {
             less.watchTimer = setInterval(() => {
                 if (less.watchMode) {
                     fileManager.clearFileCache();
+                    /**
+                     * @todo remove when this is typed with JSDoc
+                     */
+                    // eslint-disable-next-line no-unused-vars
                     loadStyleSheets((e, css, _, sheet, webInfo) => {
                         if (e) {
                             errors.add(e, e.href || sheet.href);
@@ -174,7 +178,7 @@ export default (window, options) => {
     //
     // Watch mode
     //
-    less.watch   = function () {
+    less.watch = function () {
         if (!less.watchMode ) {
             less.env = 'development';
             initRunningMode();
@@ -205,7 +209,7 @@ export default (window, options) => {
     // Asynchronously get all <link> tags with the 'rel' attribute set to
     // "stylesheet/less", returning a Promise.
     //
-    less.registerStylesheets = () => new Promise((resolve, reject) => {
+    less.registerStylesheets = () => new Promise((resolve) => {
         less.registerStylesheetsImmediately();
         resolve();
     });

packages/less/src/less-browser/plugin-loader.js

@@ -1,6 +1,6 @@
-// TODO: Add tests for browser @plugin
-/* global window */
-
+/**
+ * @todo Add tests for browser `@plugin`
+ */
 import AbstractPluginLoader from '../less/environment/abstract-plugin-loader.js';
 
 /**

packages/less/src/less-browser/utils.js

@@ -1,17 +1,17 @@
 
 export function extractId(href) {
-    return href.replace(/^[a-z-]+:\/+?[^\/]+/, '')  // Remove protocol & domain
-        .replace(/[\?\&]livereload=\w+/, '')        // Remove LiveReload cachebuster
+    return href.replace(/^[a-z-]+:\/+?[^/]+/, '')  // Remove protocol & domain
+        .replace(/[?&]livereload=\w+/, '')        // Remove LiveReload cachebuster
         .replace(/^\//, '')                         // Remove root /
         .replace(/\.[a-zA-Z]+$/, '')                // Remove simple extension
-        .replace(/[^\.\w-]+/g, '-')                 // Replace illegal characters
+        .replace(/[^.\w-]+/g, '-')                 // Replace illegal characters
         .replace(/\./g, ':');                       // Replace dots with colons(for valid id)
 }
 
 export function addDataAttr(options, tag) {
     if (!tag) {return;} // in case of tag is null or undefined
     for (const opt in tag.dataset) {
-        if (tag.dataset.hasOwnProperty(opt)) {
+        if (Object.prototype.hasOwnProperty.call(tag.dataset, opt)) {
             if (opt === 'env' || opt === 'dumpLineNumbers' || opt === 'rootpath' || opt === 'errorReporting') {
                 options[opt] = tag.dataset[opt];
             } else {

packages/less/src/less-node/file-manager.js

@@ -61,6 +61,23 @@ FileManager.prototype = Object.assign(new AbstractFileManager(), {
 
         function getFileData(fulfill, reject) {
             (function tryPathIndex(i) {
+                function tryWithExtension() {
+                    const extFilename = options.ext ? self.tryAppendExtension(fullFilename, options.ext) : fullFilename;
+
+                    if (extFilename !== fullFilename && !explicit && paths[i] === '.') {
+                        try {
+                            fullFilename = require.resolve(extFilename);
+                            isNodeModule = true;
+                        }
+                        catch (e) {
+                            filenamesTried.push(npmPrefix + extFilename);
+                            fullFilename = extFilename;
+                        }
+                    }
+                    else {
+                        fullFilename = extFilename;
+                    }
+                }
                 if (i < paths.length) {
                     (function tryPrefix(j) {
                         if (j < prefixes.length) {
@@ -83,25 +100,7 @@ FileManager.prototype = Object.assign(new AbstractFileManager(), {
                             }
                             else {
                                 tryWithExtension();
-                            }
-
-                            function tryWithExtension() {
-                                const extFilename = options.ext ? self.tryAppendExtension(fullFilename, options.ext) : fullFilename;
-
-                                if (extFilename !== fullFilename && !explicit && paths[i] === '.') {
-                                    try {
-                                        fullFilename = require.resolve(extFilename);
-                                        isNodeModule = true;
-                                    }
-                                    catch (e) {
-                                        filenamesTried.push(npmPrefix + extFilename);
-                                        fullFilename = extFilename;
-                                    }
-                                }
-                                else {
-                                    fullFilename = extFilename;
-                                }
-                            }
+                            }                            
 
                             const readFileArgs = [fullFilename];
                             if (!options.rawBuffer) {

packages/less/src/less-node/lessc-helper.js

@@ -88,4 +88,5 @@ const lessc_helper = {
 };
 
 // Exports helper functions
+// eslint-disable-next-line no-prototype-builtins
 for (const h in lessc_helper) { if (lessc_helper.hasOwnProperty(h)) { exports[h] = lessc_helper[h]; }}

packages/less/src/less-node/url-file-manager.js

@@ -1,3 +1,8 @@
+/* eslint-disable no-unused-vars */
+/**
+ * @todo - remove top eslint rule when FileManagers have JSDoc type
+ * and are TS-type-checked
+ */
 const isUrlRe = /^(?:https?:)?\/\//i;
 import url from 'url';
 let request;

packages/less/src/less/contexts.js

@@ -6,7 +6,7 @@ const copyFromOriginal = function copyFromOriginal(original, destination, proper
     if (!original) { return; }
 
     for (let i = 0; i < propertiesToCopy.length; i++) {
-        if (original.hasOwnProperty(propertiesToCopy[i])) {
+        if (Object.prototype.hasOwnProperty.call(original, propertiesToCopy[i])) {
             destination[propertiesToCopy[i]] = original[propertiesToCopy[i]];
         }
     }
@@ -113,7 +113,7 @@ contexts.Eval.prototype.pathRequiresRewrite = function (path) {
 contexts.Eval.prototype.rewritePath = function (path, rootpath) {
     let newPath;
 
-    rootpath = rootpath || '';
+    rootpath = rootpath || '';
     newPath = this.normalizePath(rootpath + path);
 
     // If a path was explicit relative and the rootpath was not an absolute path

packages/less/src/less/environment/abstract-file-manager.js

@@ -15,7 +15,7 @@ class AbstractFileManager {
     }
 
     tryAppendExtension(path, ext) {
-        return /(\.[a-z]*$)|([\?;].*)$/.test(path) ? path : path + ext;
+        return /(\.[a-z]*$)|([?;].*)$/.test(path) ? path : path + ext;
     }
 
     tryAppendLessExtension(path) {
@@ -71,15 +71,21 @@ class AbstractFileManager {
         return diff;
     }
 
-    // helper function, not part of API
+    /**
+     * Helper function, not part of API.
+     * This should be replaceable by newer Node / Browser APIs
+     * 
+     * @param {string} url 
+     * @param {string} baseUrl
+     */
     extractUrlParts(url, baseUrl) {
         // urlParts[1] = protocol://hostname/ OR /
         // urlParts[2] = / if path relative to host base
         // urlParts[3] = directories
         // urlParts[4] = filename
         // urlParts[5] = parameters
 
-        const urlPartsRegex = /^((?:[a-z-]+:)?\/{2}(?:[^\/\?#]*\/)|([\/\\]))?((?:[^\/\\\?#]*[\/\\])*)([^\/\\\?#]*)([#\?].*)?$/i;
+        const urlPartsRegex = /^((?:[a-z-]+:)?\/{2}(?:[^/?#]*\/)|([/\\]))?((?:[^/\\?#]*[/\\])*)([^/\\?#]*)([#?].*)?$/i;
 
         const urlParts = url.match(urlPartsRegex);
         const returner = {};