.eslintrc.json

{
  "env": {
    "browser": true,
    // "commonjs": true,
    // "es6": true,
    "es2020": true,
    "jest": true,
    "node": true, // For jest, config files, etc...
    "amd": true,
    "mocha": true
  },

  "parser": "@typescript-eslint/parser",

  "parserOptions": {
    // Configure the parser with the tsconfig file in the root project
    // (or rather an extended version that add peripheral files such as rollup.config.js
    // so that eslint doesn't complain that they are not in the project)
    "project": "./tsconfig.eslint.json",

    // "ecmaFeatures": { "jsx": false }, // default
    "ecmaVersion": 2020,
    // "sourceType": "module" // Allow the use of import
    "extraFileExtensions": [".less"]
  },

  "extends": [
    // Uses the recommended rules for Typescript
    "plugin:@typescript-eslint/recommended",
    "plugin:prettier/recommended"

    // "plugin:no-unsanitized/DOM"
  ],

  // Note:
  // "off" or 0 - turn the rule off
  // "warn" or 1 - turn the rule on as a warning (doesn’t affect exit code)
  // "error" or 2 - turn the rule on as an error (exit code is 1 when triggered)
  // See http://eslint.org/docs/rules/
  "rules": {
    // "no-unsanitized/method": [
    //     "warn",
    //     {
    //         // "disableDefault": true,
    //         "escape": {
    //             "methods": [
    //                 "createHTML",
    //                 "mathfield.config.createHTML",
    //                 "MathfieldPrivate.config.createHTML"
    //             ]
    //         }
    //     }
    // ],
    "no-restricted-globals": [
      "error",
      "postMessage",
      "blur",
      "focus",
      "close",
      "frames",
      "self",
      "parent",
      "opener",
      "top",
      "length",
      "closed",
      "location",
      "origin",
      "name",
      "locationbar",
      "menubar",
      "personalbar",
      "scrollbars",
      "statusbar",
      "toolbar",
      "status",
      "frameElement",
      // "navigator",
      "customElements",
      "external",
      "screen",
      "innerWidth",
      "innerHeight",
      "scrollX",
      "pageXOffset",
      "scrollY",
      "pageYOffset",
      "screenX",
      "screenY",
      "outerWidth",
      "outerHeight",
      "devicePixelRatio",
      "clientInformation",
      "screenLeft",
      "screenTop",
      "defaultStatus",
      "defaultstatus",
      "styleMedia",
      "onanimationend",
      "onanimationiteration",
      "onanimationstart",
      "onsearch",
      "ontransitionend",
      "onwebkitanimationend",
      "onwebkitanimationiteration",
      "onwebkitanimationstart",
      "onwebkittransitionend",
      "isSecureContext",
      "onabort",
      "onblur",
      "oncancel",
      "oncanplay",
      "oncanplaythrough",
      "onchange",
      "onclick",
      "onclose",
      "oncontextmenu",
      "oncuechange",
      "ondblclick",
      "ondrag",
      "ondragend",
      "ondragenter",
      "ondragleave",
      "ondragover",
      "ondragstart",
      "ondrop",
      "ondurationchange",
      "onemptied",
      "onended",
      "onerror",
      "onfocus",
      "oninput",
      "oninvalid",
      "onkeydown",
      "onkeypress",
      "onkeyup",
      "onload",
      "onloadeddata",
      "onloadedmetadata",
      "onloadstart",
      "onmousedown",
      "onmouseenter",
      "onmouseleave",
      "onmousemove",
      "onmouseout",
      "onmouseover",
      "onmouseup",
      "onmousewheel",
      "onpause",
      "onplay",
      "onplaying",
      "onprogress",
      "onratechange",
      "onreset",
      "onresize",
      "onscroll",
      "onseeked",
      "onseeking",
      "onselect",
      "onstalled",
      "onsubmit",
      "onsuspend",
      "ontimeupdate",
      "ontoggle",
      "onvolumechange",
      "onwaiting",
      "onwheel",
      "onauxclick",
      "ongotpointercapture",
      "onlostpointercapture",
      "onpointerdown",
      "onpointermove",
      "onpointerup",
      "onpointercancel",
      "onpointerover",
      "onpointerout",
      "onpointerenter",
      "onpointerleave",
      "onafterprint",
      "onbeforeprint",
      "onbeforeunload",
      "onhashchange",
      "onlanguagechange",
      "onmessage",
      "onmessageerror",
      "onoffline",
      "ononline",
      "onpagehide",
      "onpageshow",
      "onpopstate",
      "onrejectionhandled",
      "onstorage",
      "onunhandledrejection",
      "onunload",
      "performance",
      "stop",
      "open",
      "print",
      "captureEvents",
      "releaseEvents",
      // "getComputedStyle",
      "matchMedia",
      "moveTo",
      "moveBy",
      "resizeTo",
      "resizeBy",
      "getSelection",
      "find",
      "createImageBitmap",
      "scroll",
      "scrollTo",
      "scrollBy",
      "onappinstalled",
      "onbeforeinstallprompt",
      "crypto",
      "ondevicemotion",
      "ondeviceorientation",
      "ondeviceorientationabsolute",
      "indexedDB",
      "webkitStorageInfo",
      "chrome",
      "visualViewport",
      "speechSynthesis",
      "webkitRequestFileSystem",
      "webkitResolveLocalFileSystemURL",
      "openDatabase"
    ],

    // Turn off rules that are Typescript specific
    // (they are turned on later in the "overrides" section)
    "@typescript-eslint/explicit-module-boundary-types": "off",

    "no-unused-expressions": "off",

    "prettier/prettier": [
      "error",
      {
        "endOfLine": "auto"
      }
    ],

    // note you must disable the base rule as it can report incorrect errors
    "indent": "off",

    "no-const-assign": "warn",
    "no-this-before-super": "warn",
    // "no-undef": "warn",
    "no-unreachable": "warn",
    "no-unused-vars": ["warn", { "argsIgnorePattern": "^_" }],
    "@typescript-eslint/no-unused-vars": [
      "warn",
      { "argsIgnorePattern": "^_" }
    ],
    "constructor-super": "warn",

    "block-scoped-var": "error",

    "array-bracket-spacing": ["error", "never"],
    "block-spacing": ["error", "always"],
    "brace-style": ["warn", "1tbs", { "allowSingleLine": true }],
    "prefer-const": "warn",

    "valid-typeof": "error",
    "consistent-return": "error",
    "curly": ["warn", "multi-or-nest"],
    "eqeqeq": ["error", "smart"],
    "guard-for-in": "warn",
    // "max-len": "warn",
    "new-cap": "warn",
    "no-bitwise": "off",
    "no-console": "off",
    "no-dupe-class-members": "off", // Support TypeScritp polymorphism
    "no-else-return": "warn",
    "no-eval": "error",
    "no-fallthrough": "error",
    "no-invalid-this": "warn",
    "no-lone-blocks": "warn",
    "no-return-assign": ["warn", "always"],
    "no-redeclare": "off",
    "no-self-compare": "error",
    "no-sequences": "warn",
    "no-unneeded-ternary": "warn",
    "no-useless-call": "warn",
    "no-var": "error",
    "no-with": "error",
    // "vars-on-top": "warn",
    "no-delete-var": "warn",
    "no-mixed-spaces-and-tabs": ["warn", "smart-tabs"],
    "require-jsdoc": "off",
    "space-infix-ops": ["error", { "int32Hint": false }],

    "no-trailing-spaces": [1, { "skipBlankLines": true }]
  },
  "overrides": [
    {
      // Typescript-specific rules
      "files": ["*.ts"],
      "rules": {
        "@typescript-eslint/no-unused-vars": [
          "error",
          {
            "argsIgnorePattern": "^_"
            // "varsIgnorePattern": "^_",
            // "vars": "all",
            // "args": "after-used",
            // "ignoreRestSiblings": false
          }
        ],
        // We use @ts-ignore to generate the .d.ts files using tsc, even though
        // they import .less file which tsc doesn't know to handle.
        "@typescript-eslint/ban-ts-comment": "off",

        // When used with optional chaining, eslint can give an incorrect warning
        "@typescript-eslint/no-unused-expressions": "warn",
        "@typescript-eslint/prefer-optional-chain": "warn",
        "@typescript-eslint/prefer-nullish-coalescing": "warn",
        "@typescript-eslint/no-empty-function": "off",
        "@typescript-eslint/naming-convention": [
          "warn",
          {
            "selector": "typeParameter",
            "format": ["PascalCase"]
          }
        ],
        "@typescript-eslint/no-non-null-assertion": "off",
        "@typescript-eslint/no-use-before-define": [
          "error",
          {
            "functions": false,
            "classes": false,
            "variables": false,
            "typedefs": false
          }
        ],
        "@typescript-eslint/no-this-alias": [
          "error",
          {
            "allowedNames": ["self", "that"] // Allow `const self = this`; `[]` by default
          }
        ],
        "@typescript-eslint/no-for-in-array": "error",

        "@typescript-eslint/explicit-function-return-type": "off",
        "@typescript-eslint/explicit-module-boundary-types": "warn",
        "@typescript-eslint/no-unnecessary-type-arguments": "warn",
        // "@typescript-eslint/typedef": [
        //     "warn",
        //     {
        //         "parameter": true,
        //         "arrowParameter": false,
        //         "variableDeclaration": false
        //     }
        // ],

        "@typescript-eslint/array-type": ["warn", { "default": "array" }],

        "@typescript-eslint/no-explicit-any": "off"
      }
    }
  ]
}