.eslintrc

{
  //github.com/eslint/eslint/blob/main/conf/eslint-recommended.js
  "extends": "eslint:recommended",
  "env": {
    "browser": true,
    "es6": true, // sets parserOptions.ecmaVersion = 6
    "jquery": true
  },
  "plugins": [
    "dollar-sign"
  ],
  //eslint.org/docs/rules/
  "rules": {
    //eslint.org/docs/latest/rules#possible-problems
    "array-callback-return": ["error"],
    "no-await-in-loop": ["error"],
    "no-constant-binary-expression": ["warn"],
    "no-constructor-return": ["warn"],
    "no-duplicate-imports": ["warn"],
    "no-new-native-nonconstructor": ["warn"],
    "no-self-compare": ["warn"],
    "no-template-curly-in-string": ["error"],
    "no-unmodified-loop-condition": ["warn"],
    "no-unreachable-loop": ["warn"],
    "no-unused-private-class-members": ["warn"],
    "no-unused-vars": ["warn", { "vars": "local", "args": "none", "ignoreRestSiblings": true }],
    "no-use-before-define": ["warn", { "functions": false }], // functions allowed client-side
    "require-atomic-updates": ["warn"],

    //eslint.org/docs/latest/rules#suggestions
    "accessor-pairs": ["warn"],
    //"arrow-body-style": ["warn", "as-needed"], // conflicts with no-confusing-arrow, ignores comments
    "block-scoped-var": ["warn"],
    "camelcase": ["warn", { "properties": "never" }],
    "class-methods-use-this": ["warn"],
    "complexity": ["warn", 40],
    //"consistent-return": ["warn"], // false positives
    //"consistent-this": ["warn", "self", "that"], // warns if self is assigned to anything other than `this`
    //"curly": ["warn", "multi-line", "consistent"], // false positives
    "default-case": ["warn"], // allows "no default" comment
    "default-case-last": ["warn"],
    "default-param-last": ["warn"],
    "dot-notation": ["warn", { "allowPattern": "^[a-z]+(_[a-z]+)+$" }],
    "eqeqeq": ["warn"],
    "func-name-matching": ["warn"],
    "grouped-accessor-pairs": ["warn", "getBeforeSet"],
    "guard-for-in": ["warn"],
    "id-denylist": ["warn"],
    //"logical-assignment-operators": ["warn", "always", { "enforceForIfStatements": true }], // future
    "max-classes-per-file": ["warn", 8],
    "max-depth": ["warn", 8],
    "max-lines": ["warn", { "max": 1000, "skipBlankLines": true, "skipComments": true }],
    "max-lines-per-function": ["warn", { "max": 350, "skipBlankLines": true, "skipComments": true }], // default 50, disable in gruntfile
    "max-nested-callbacks": ["warn", 10], // default 10
    "max-params": ["warn", 10],
    "max-statements": ["warn", 100],
    //"new-cap": ["warn"], // necessary for some third-party modules
    "no-array-constructor": ["warn"],
    "no-bitwise": ["warn"],
    "no-caller": ["error"],
    "no-confusing-arrow": ["warn"],
    "no-div-regex": ["warn"],
    "no-else-return": ["warn"],
    "no-empty": ["warn"],
    "no-empty-function": ["warn"],
    "no-empty-static-block": ["warn"],
    "no-eq-null": ["warn"],
    "no-eval": ["error"],
    "no-extend-native": ["warn"],
    "no-extra-bind": ["warn"],
    "no-extra-label": ["warn"],
    "no-floating-decimal": ["warn"],
    "no-global-assign": ["warn", { "exceptions": ["location"] }],
    "no-implicit-coercion": ["warn", { "boolean": true, "string": false, "number": true }],
    "no-implied-eval": ["warn"],
    "no-invalid-this": ["warn"],
    "no-iterator": ["warn"],
    "no-label-var": ["warn"],
    "no-labels": ["warn"], //["warn", { "allowLoop": true }],
    "no-lone-blocks": ["warn"],
    "no-lonely-if": ["warn"],
    "no-loop-func": ["warn"],
    "no-mixed-operators": ["warn"],
    "no-multi-assign": ["warn"],
    "no-multi-str": ["warn"],
    "no-negated-condition": ["warn"],
    "no-new": ["warn"],
    "no-new-func": ["error"],
    "no-new-object": ["warn"],
    "no-new-wrappers": ["warn"],
    "no-octal-escape": ["warn"],
    "no-param-reassign": ["warn"],
    "no-proto": ["warn"],
    "no-restricted-exports": ["warn"],
    "no-restricted-globals": ["warn"],
    "no-restricted-imports": ["warn"],
    "no-restricted-properties": ["warn"],
    "no-restricted-syntax": ["warn"],
    "no-return-assign": ["warn"],
    "no-return-await": ["warn"],
    "no-script-url": ["warn"],
    "no-sequences": ["warn"],
    "no-throw-literal": ["warn"],
    "no-undef-init": ["warn"],
    "no-undefined": ["warn"],
    "no-unneeded-ternary": ["warn"],
    "no-unused-expressions": ["warn"],
    "no-useless-call": ["warn"],
    "no-useless-computed-key": ["warn"],
    "no-useless-concat": ["error"],
    "no-useless-constructor": ["warn"],
    "no-useless-rename": ["warn"],
    "no-useless-return": ["warn"],
    "no-void": ["warn"],
    "no-warning-comments": ["warn", { "terms": ["fixme", "hack"] }],
    "one-var": ["warn", { "const": "never", "let": "never", "separateRequires": true }],
    "operator-assignment": ["warn"],
    "prefer-destructuring": ["off"], // BUG: supposedly not included in eslint:recommended, but warns even when off
    "prefer-exponentiation-operator": ["warn"],
    //"prefer-named-capture-group": ["warn"], // future?
    "prefer-promise-reject-errors": ["warn"],
    "prefer-regex-literals": ["warn"],
    "quote-props": ["warn", "as-needed"],
    "radix": ["warn", "as-needed"],
    "require-await": ["warn"],
    "sort-imports": ["warn", { "ignoreCase": true, "ignoreDeclarationSort": true }],
    "symbol-description": ["warn"],
    "yoda": ["warn"],

    //eslint.org/docs/latest/rules/#layout--formatting
    "array-bracket-spacing": ["warn", "never"],
    "arrow-parens": ["warn"],
    "arrow-spacing": ["warn"],
    "block-spacing": ["warn"],
    "brace-style": ["warn", "1tbs"],
    "comma-dangle": ["warn", "only-multiline"],
    "comma-spacing": ["warn", { "before": false, "after": true }],
    "comma-style": ["warn", "last"],
    "computed-property-spacing": ["warn", "never"],
    "dot-location": ["warn", "property"],
    "eol-last": ["error"],
    "func-call-spacing": ["warn", "never"],
    "function-call-argument-newline": ["warn", "consistent"],
    "function-paren-newline": ["warn", "consistent"],
    "generator-star-spacing": ["warn"],
    "implicit-arrow-linebreak": ["warn"],
    "indent": ["warn", 2, {
      "FunctionExpression": { "parameters": "first" },
      "MemberExpression": 1,
      "SwitchCase": 1,
      "VariableDeclarator": { "var": 2, "let": 2, "const": 3 }
    }],
    "key-spacing": ["warn", { "beforeColon": false, "afterColon": true }],
    "linebreak-style": ["warn", "unix"],
    "lines-between-class-members": ["warn"],
    "max-len": ["warn", { "code": 180, "ignoreTemplateLiterals": true, "ignoreUrls": true }],
    "max-statements-per-line": ["warn", { "max": 2 }],
    "multiline-ternary": ["warn", "always-multiline"],
    "new-parens": ["warn"],
    //"no-extra-parens": ["warn", "all", { "conditionalAssign": false, "enforceForArrowConditionals": false, "ignoreJSX": "all", "nestedBinaryExpressions": false, "returnAssign": false }],
    "no-multi-spaces": ["warn", { "ignoreEOLComments": true, "exceptions": { "ImportDeclaration": true, "Property": true, "VariableDeclarator": true } }],
    "no-multiple-empty-lines": ["warn", { "max": 3, "maxEOF": 0 }],
    //"no-tabs": ["warn"], // warns about tabs in comments
    "no-trailing-spaces": ["warn"],
    "no-whitespace-before-property": ["warn"],
    "object-curly-spacing": ["warn", "always"],
    "operator-linebreak": ["warn", "after", { "overrides": { "?": "before", ":": "before" } }],
    "padded-blocks": ["warn", { "blocks": "never", "switches": "never" }],
    "padding-line-between-statements": ["warn"],
    "quotes": ["warn", "single", { "avoidEscape": true, "allowTemplateLiterals": true }],
    "rest-spread-spacing": ["warn"],
    "semi": ["warn", "always"],
    "semi-spacing": ["warn", { "before": false, "after": true }],
    "semi-style": ["warn"],
    "space-before-blocks": ["warn"],
    "space-before-function-paren": ["warn", { "anonymous": "always", "named": "never", "asyncArrow": "always" }],
    "space-in-parens": ["warn"],
    "space-infix-ops": ["warn"],
    "space-unary-ops": ["warn", { "words": true, "nonwords": false }],
    "switch-colon-spacing": ["warn"],
    "template-curly-spacing": ["warn"],
    "template-tag-spacing": ["warn"],
    "unicode-bom": ["warn"],
    "wrap-iife": ["warn"],
    "wrap-regex": ["warn"],
    "yield-star-spacing": ["warn"],

    //eslint.org/docs/rules/#deprecated
    "callback-return": ["warn"],
    "no-buffer-constructor": ["warn"],
    "no-mixed-requires": ["warn"],
    "no-new-require": ["warn"],
    "no-path-concat": ["warn"],
    "no-process-exit": ["warn"],
    "no-prototype-builtins": ["error"],
    "no-restricted-modules": ["warn"],
    "no-sync": ["warn"],

    // PLUGINS //
    //www.npmjs.com/package/eslint-plugin-dollar-sign
    "dollar-sign/dollar-sign": ["warn", "ignoreProperties"]
  }
}