chore: set up eslint for jest

.eslintrc.js

@@ -1,21 +1,68 @@
 module.exports = {
-    "env": {
-        "browser": true,
-        "es2021": true,
-    },
-    "extends": [
-        "eslint:recommended",
-        "plugin:@typescript-eslint/recommended"
+    root: true,
+    ignorePatterns: [
+        // Ignore build artifacts
+        '/node_modules',
+        '/dist',
+
+        // Ignore playground
+        '/examples'
     ],
-    "parser": "@typescript-eslint/parser",
-    "parserOptions": {
-        "ecmaVersion": "latest",
-        "sourceType": "module"
+    parserOptions: {
+        ecmaVersion: 2020,
+        sourceType: 'module'
     },
-    "plugins": [
-        "@typescript-eslint"
+    plugins: [
+        'import',
+        'jest'
     ],
-    "rules": {
-        "@typescript-eslint/no-explicit-any": 0
+    rules: {
+        'import/no-deprecated': [
+            'warn'
+        ],
+        'brace-style': [
+            'warn',
+            '1tbs',
+            {
+                'allowSingleLine': true
+            }
+        ],
+        'capitalized-comments': [
+            'off',
+            'never'
+        ],
+        'comma-dangle': 'error',
+        'default-case': 'error',
+        'dot-notation': 'off',
+        'id-denylist': [
+            'error',
+            'String',
+            'string',
+            'Boolean',
+            'boolean',
+            'Undefined',
+            'undefined'
+        ],
+
+        'indent': [
+            'warn',
+            4
+        ],
+        'no-empty': 'error',
+        'no-empty-function': 'off',
+        'no-redeclare': 'error',
+        'no-shadow': 'off',
+        'no-unused-expressions': 'warn',
+        'no-use-before-define': 'off',
+        'semi': 'error',
+
+        // Jest rules
+        "jest/no-disabled-tests": "off",
+        "jest/no-focused-tests": "error",
+        "jest/no-identical-title": "warn",
+        "jest/prefer-spy-on": "warn",
+        "jest/prefer-to-be": "warn",
+        "jest/prefer-to-have-length": "warn",
+        "jest/valid-expect": "error"
     }
-}
+};

package.json

@@ -11,9 +11,9 @@
   "typings": "dist/npm/main.d.ts",
   "scripts": {
     "build-package": "gulp build-rollup-package build-cdn",
-    "test": "jest -- test/",
-    "locale-tests": "jest -- locale-tests/",
-    "lint": "eslint ./src",
+    "test": "jest -- ./test",
+    "locale-tests": "jest -- ./locale-tests",
+    "lint": "eslint --quiet -- ./src ./test ./locale-tests/*.js",
     "semantic-release": "semantic-release pre && semantic-prerelease publish && semantic-release post"
   },
   "keywords": [
@@ -34,6 +34,8 @@
     "cz-conventional-changelog": "^1.1.5",
     "es-jest": "^1.5.0",
     "eslint": "^8.16.0",
+    "eslint-plugin-import": "^2.26.0",
+    "eslint-plugin-jest": "^26.5.3",
     "ghooks": "^1.0.3",
     "gulp": "^4.0.0",
     "jest-cli": "^26.6.3",

test/cldr.test.js

@@ -1,5 +1,18 @@
-import { load, cldr, localeInfo, dateFieldName, dateFormatNames, firstDay, weekendRange,
-    localeCurrency, currencyDisplay, currencyFractionOptions, currencyDisplays, numberSymbols, setData } from '../src/cldr';
+import {
+    cldr,
+    currencyDisplay,
+    currencyDisplays,
+    currencyFractionOptions,
+    dateFieldName,
+    dateFormatNames,
+    firstDay,
+    load,
+    localeCurrency,
+    localeInfo,
+    numberSymbols,
+    setData,
+    weekendRange
+    } from '../src/cldr';
 import { errors } from '../src/errors';
 
 const likelySubtags = require("cldr-core/supplemental/likelySubtags.json");
@@ -124,10 +137,10 @@ describe('load numbers', () => {
                         },
                         "currencyFormats-numberSystem-latn":{
                             standard: "¤ #,##0.00 bar",
-                            accounting: "foo #,##0.00 ¤",
+                            accounting: "foo #,##0.00 ¤"
                         },
                         "percentFormats-numberSystem-latn": {
-                            standard: "% #,##0.00 bar",
+                            standard: "% #,##0.00 bar"
                         }
                     }
                 }