feat: Flat config support in Linter (refs #13481)

conf/globals.js

@@ -0,0 +1,144 @@
+/**
+ * @fileoverview Globals for ecmaVersion/sourceType
+ * @author Nicholas C. Zakas
+ */
+
+"use strict";
+
+//-----------------------------------------------------------------------------
+// Globals
+//-----------------------------------------------------------------------------
+
+const commonjs = {
+    exports: true,
+    global: false,
+    module: false,
+    require: false
+};
+
+const es3 = {
+    Array: false,
+    Boolean: false,
+    constructor: false,
+    Date: false,
+    decodeURI: false,
+    decodeURIComponent: false,
+    encodeURI: false,
+    encodeURIComponent: false,
+    Error: false,
+    escape: false,
+    eval: false,
+    EvalError: false,
+    Function: false,
+    hasOwnProperty: false,
+    Infinity: false,
+    isFinite: false,
+    isNaN: false,
+    isPrototypeOf: false,
+    Math: false,
+    NaN: false,
+    Number: false,
+    Object: false,
+    parseFloat: false,
+    parseInt: false,
+    propertyIsEnumerable: false,
+    RangeError: false,
+    ReferenceError: false,
+    RegExp: false,
+    String: false,
+    SyntaxError: false,
+    toLocaleString: false,
+    toString: false,
+    TypeError: false,
+    undefined: false,
+    unescape: false,
+    URIError: false,
+    valueOf: false
+};
+
+const es5 = {
+    ...es3,
+    JSON: false
+};
+
+const es2015 = {
+    ...es5,
+    ArrayBuffer: false,
+    DataView: false,
+    Float32Array: false,
+    Float64Array: false,
+    Int16Array: false,
+    Int32Array: false,
+    Int8Array: false,
+    Map: false,
+    Promise: false,
+    Proxy: false,
+    Reflect: false,
+    Set: false,
+    Symbol: false,
+    Uint16Array: false,
+    Uint32Array: false,
+    Uint8Array: false,
+    Uint8ClampedArray: false,
+    WeakMap: false,
+    WeakSet: false
+};
+
+// no new globals in ES2016
+const es2016 = {
+    ...es2015
+};
+
+const es2017 = {
+    ...es2016,
+    Atomics: false,
+    SharedArrayBuffer: false
+};
+
+// no new globals in ES2018
+const es2018 = {
+    ...es2017
+};
+
+// no new globals in ES2019
+const es2019 = {
+    ...es2018
+};
+
+const es2020 = {
+    ...es2019,
+    BigInt: false,
+    BigInt64Array: false,
+    BigUint64Array: false,
+    globalThis: false
+};
+
+const es2021 = {
+    ...es2020,
+    AggregateError: false,
+    FinalizationRegistry: false,
+    WeakRef: false
+};
+
+const es2022 = {
+    ...es2021
+};
+
+
+//-----------------------------------------------------------------------------
+// Exports
+//-----------------------------------------------------------------------------
+
+module.exports = {
+    commonjs,
+    es3,
+    es5,
+    es2015,
+    es2016,
+    es2017,
+    es2018,
+    es2019,
+    es2020,
+    es2021,
+    es2022
+};

karma.conf.js

@@ -16,6 +16,15 @@ module.exports = function(config) {
         // base path that will be used to resolve all patterns (eg. files, exclude)
         basePath: "",
 
+        // next three sections allow console.log to work
+        client: {
+            captureConsole: true
+        },
+
+        browserConsoleLogOptions: {
+            terminal: true,
+            level: "log"
+        },
 
         /*
          * frameworks to use

lib/config/default-config.js

@@ -26,7 +26,7 @@ exports.defaultConfig = [
 
                 /*
                  * Because we try to delay loading rules until absolutely
-                 * necessary, a proxy  allows us to hook into the lazy-loading
+                 * necessary, a proxy allows us to hook into the lazy-loading
                  * aspect of the rules map while still keeping all of the
                  * relevant configuration inside of the config array.
                  */
@@ -46,7 +46,16 @@ exports.defaultConfig = [
             ".git/**"
         ],
         languageOptions: {
-            parser: "@/espree"
+            ecmaVersion: "latest",
+            sourceType: "module",
+            parser: "@/espree",
+            parserOptions: {}
+        }
+    },
+    {
+        files: ["**/*.cjs"],
+        languageOptions: {
+            sourceType: "commonjs"
         }
     }
 ];

lib/config/flat-config-array.js

@@ -52,13 +52,13 @@ class FlatConfigArray extends ConfigArray {
      * @param {{basePath: string, baseConfig: FlatConfig}} options The options
      *      to use for the config array instance.
      */
-    constructor(configs, { basePath, baseConfig = defaultConfig }) {
+    constructor(configs, { basePath, baseConfig = defaultConfig } = {}) {
         super(configs, {
             basePath,
             schema: flatConfigSchema
         });
 
-        this.unshift(baseConfig);
+        this.unshift(...baseConfig);
     }
 
     /* eslint-disable class-methods-use-this -- Desired as instance method */

lib/config/flat-config-helpers.js

@@ -0,0 +1,67 @@
+/**
+ * @fileoverview Shared functions to work with configs.
+ * @author Nicholas C. Zakas
+ */
+
+"use strict";
+
+//-----------------------------------------------------------------------------
+// Functions
+//-----------------------------------------------------------------------------
+
+/**
+ * Parses a ruleId into its plugin and rule parts.
+ * @param {string} ruleId The rule ID to parse.
+ * @returns {{pluginName:string,ruleName:string}} The plugin and rule
+ *      parts of the ruleId;
+ */
+function parseRuleId(ruleId) {
+    let pluginName, ruleName;
+
+    // distinguish between core rules and plugin rules
+    if (ruleId.includes("/")) {
+        pluginName = ruleId.slice(0, ruleId.lastIndexOf("/"));
+        ruleName = ruleId.slice(pluginName.length + 1);
+    } else {
+        pluginName = "@";
+        ruleName = ruleId;
+    }
+
+    return {
+        pluginName,
+        ruleName
+    };
+}
+
+/**
+ * Retrieves a rule instance from a given config based on the ruleId.
+ * @param {string} ruleId The rule ID to look for.
+ * @param {FlatConfig} config The config to search.
+ * @returns {import("../shared/types").Rule|undefined} The rule if found
+ *      or undefined if not.
+ */
+function getRuleFromConfig(ruleId, config) {
+
+    const { pluginName, ruleName } = parseRuleId(ruleId);
+
+    const plugin = config.plugins && config.plugins[pluginName];
+    let rule = plugin && plugin.rules && plugin.rules[ruleName];
+
+    // normalize function rules into objects
+    if (rule && typeof rule === "function") {
+        rule = {
+            create: rule
+        };
+    }
+
+    return rule;
+}
+
+//-----------------------------------------------------------------------------
+// Exports
+//-----------------------------------------------------------------------------
+
+module.exports = {
+    parseRuleId,
+    getRuleFromConfig
+};

lib/config/flat-config-schema.js

@@ -195,13 +195,6 @@ function assertIsObjectOrString(value) {
 // Low-Level Schemas
 //-----------------------------------------------------------------------------
 
-
-/** @type {ObjectPropertySchema} */
-const numberSchema = {
-    merge: "replace",
-    validate: "number"
-};
-
 /** @type {ObjectPropertySchema} */
 const booleanSchema = {
     merge: "replace",
@@ -415,6 +408,18 @@ const rulesSchema = {
     }
 };
 
+/** @type {ObjectPropertySchema} */
+const ecmaVersionSchema = {
+    merge: "replace",
+    validate(value) {
+        if (typeof value === "number" || value === "latest") {
+            return;
+        }
+
+        throw new TypeError("Expected a number or \"latest\".");
+    }
+};
+
 /** @type {ObjectPropertySchema} */
 const sourceTypeSchema = {
     merge: "replace",
@@ -439,7 +444,7 @@ exports.flatConfigSchema = {
     },
     languageOptions: {
         schema: {
-            ecmaVersion: numberSchema,
+            ecmaVersion: ecmaVersionSchema,
             sourceType: sourceTypeSchema,
             globals: globalsSchema,
             parser: parserSchema,