.eslintrc

{
    "parser": "@typescript-eslint/parser",
    "extends": [
        "mourner",
        "plugin:import/recommended",
        "plugin:import/typescript",
        "plugin:@typescript-eslint/recommended-type-checked"
    ],
    "parserOptions": {
        "projectService": {
            "defaultProject": "./tsconfig.json",
            "allowDefaultProject": ["*.js"]
        }
    },
    "plugins": [
        "jsdoc",
        "import",
        "@typescript-eslint"
    ],
    "settings": {
        "import/parsers": {
            "@typescript-eslint/parser": [".ts"]
        },
        "import/resolver": {
            "node": true,
            "typescript": {
                "project": "./tsconfig.json"
            }
        },
        "jsdoc": {
            "ignorePrivate": true,
            "preferredTypes": {
                "object": "Object"
            }
        }
    },
    "rules": {
        // temporarily disabled for easier migration to TypeScript
        "no-loss-of-precision": "off",
        "@typescript-eslint/no-this-alias": "off",
        "@typescript-eslint/ban-ts-comment": "off",
        "@typescript-eslint/unbound-method": "off",
        "@typescript-eslint/no-unsafe-call": "off",
        "@typescript-eslint/no-explicit-any": "off",
        "@typescript-eslint/no-unsafe-return": "off",
        "@typescript-eslint/no-unsafe-argument": "off",
        "@typescript-eslint/no-unsafe-assignment": "off",
        "@typescript-eslint/no-loss-of-precision": "off",
        "@typescript-eslint/no-unsafe-member-access": "off",
        "@typescript-eslint/only-throw-error": "off",

        // TypeScript specific rules
        "@typescript-eslint/method-signature-style": "error",
        "@typescript-eslint/no-floating-promises": "off",
        "@typescript-eslint/consistent-type-exports": "error",
        "@typescript-eslint/consistent-type-imports": "error",
        "@typescript-eslint/restrict-template-expressions": ["off", { "allowNever": true }],
        "@typescript-eslint/no-unnecessary-type-constraint": "off",
        "no-unused-vars": "off",
        "@typescript-eslint/no-unused-vars": ["error", {
            "args": "none",
            "caughtErrors": "none",
            "ignoreRestSiblings": true
        }],

        // Disable those rules since TypeScript provides the same checks as part of standard type checking
        // See https://typescript-eslint.io/troubleshooting/performance-troubleshooting/#eslint-plugin-import
        "import/named": "off",
        "import/namespace": "off",
        "import/default": "off",
        "import/no-named-as-default-member": "off",
        "import/no-unresolved": "off",
        "import/no-named-as-default": "off",

        // Import plugin rules
        "no-duplicate-imports": "off",
        "import/no-duplicates": "error",

        "import/order": ["error", {
            "groups": [["builtin", "external", "internal", "unknown", "parent", "sibling", "index", "object"], "type"],
            "newlines-between": "always"
        }],

        // Restrict imports outside of the style-spec
        "import/no-restricted-paths": ["error", {
            "zones": [{
                "target": "./src/style-spec",
                "from": ["./src/!(style-spec)/**/*", "./3d-style/**/*"]
            }]
        }],

        // ensure compatibility with Node's native ESM
        "import/extensions": ["error", {
            "js": "always",
            "json": "always"
        }],

        // temporarily disabled for easier upgrading of dependencies
        "no-use-before-define": "off",
        "implicit-arrow-linebreak": "off",
        "arrow-parens": "off",
        "arrow-body-style": "off",
        "no-confusing-arrow": "off",
        "no-control-regex": "off",
        "no-invalid-this": "off",
        "no-prototype-builtins": "off",
        "accessor-pairs": "off",
        "require-atomic-updates": "off",

        "array-bracket-spacing": "off",
        "consistent-return": "off",
        "global-require": "off",
        "import/no-commonjs": "error",
        "key-spacing": "off",
        "no-eq-null": "off",
        "no-lonely-if": "off",
        "no-new": "off",
        "no-warning-comments": "error",
        "no-mixed-operators": ["error", { "groups": [["&", "|", "^", "~", "<<", ">>", ">>>"], ["&&", "||"]] }],
        "object-curly-spacing": ["error", "never"],
        "prefer-arrow-callback": "error",
        "prefer-const": ["error", { "destructuring": "all" }],
        "prefer-template": "error",
        "quotes": "off",
        "space-before-function-paren": "off",
        "template-curly-spacing": "error",
        "no-useless-escape": "off",
        "indent": ["error", 4, {
            "flatTernaryExpressions": true,
            "CallExpression": {
                "arguments": "off"
            },
            "FunctionDeclaration": {
                "parameters": "off"
            },
            "FunctionExpression": {
                "parameters": "off"
            }
        }],
        "no-multiple-empty-lines": ["error", {
            "max": 1
        }]
    },
    "overrides": [
        {
            "files": ["src/render/draw_sky.ts"],
            "rules": { "@typescript-eslint/no-base-to-string": "off" }
        },
        {
            "files": ["src/style/style_layer.ts"],
            "rules": { "no-self-assign": "off" }
        },
        {
            "files": ["src/terrain/terrain.ts"],
            "rules": { "@typescript-eslint/no-base-to-string": "off" }
        },
        {
            "files": ["src/util/util.ts"],
            "rules": { "@typescript-eslint/restrict-plus-operands": "off" }
        },
        {
            "files": ["build/**", "debug/**", "bench/**", "test/**", "src/style-spec/**"],
            "rules": {
                "jsdoc/check-param-names": "off",
                "jsdoc/require-param": "off",
                "jsdoc/require-param-description": "off",
                "jsdoc/require-param-name": "off",
                "jsdoc/require-returns": "off",
                "jsdoc/require-returns-description": "off",
                "jsdoc/require-property": "off",
                "jsdoc/require-description-complete-sentence": "off",
                "jsdoc/check-access": "off",
                "jsdoc/check-examples": "off",
                "jsdoc/check-line-alignment": "off",
                "jsdoc/check-property-names": "off",
                "jsdoc/check-types": "off",
                "jsdoc/tag-lines": "off",
                "jsdoc/require-description": "off",
                "jsdoc/require-example": "off",
                "jsdoc/require-param-type": "off",
                "jsdoc/require-property-description": "off",
                "jsdoc/require-property-name": "off",
                "jsdoc/require-property-type": "off",
                "jsdoc/require-returns-type": "off",
            }
        },
        {
            "files": [
                "src/index.ts",
                "src/ui/map.ts",
                "src/ui/camera.ts",
                "src/ui/marker.ts",
                "src/ui/popup.ts",
                "src/ui/events.ts",
                "src/ui/control/**",
                "src/ui/handler/**",
                "src/geo/lng_lat.ts",
                "src/geo/mercator_coordinate.ts",
                "src/source/**",
            ],
            "rules": {
                "jsdoc/check-param-names": "error",
                "jsdoc/require-param": "error",
                "jsdoc/require-param-description": "error",
                "jsdoc/require-param-name": "error",
                "jsdoc/require-returns": "error",
                "jsdoc/require-returns-description": "error",
                "jsdoc/require-property": "error",
                "jsdoc/require-description-complete-sentence": "error",
                "jsdoc/check-access": "error",
                // temporarily disabled for easier migration to TypeScript
                // "jsdoc/check-examples": ["error", {
                //   "matchingFileName": "src/fake_filename_for_jsdoc_examples",
                //   "rejectExampleCodeRegex": "<script>"
                // }],
                "jsdoc/check-line-alignment": ["error"],
                "jsdoc/check-property-names": "error",
                "jsdoc/check-types": "error",
                "jsdoc/tag-lines": ["error", "any", { "startLines": 1 }],
                "jsdoc/require-description": "error",
                "jsdoc/require-example": "error",
                "jsdoc/require-param-type": "error",
                "jsdoc/require-property-description": "error",
                "jsdoc/require-property-name": "error",
                "jsdoc/require-property-type": "error",
                "jsdoc/require-returns-type": "error",
            }
        },
        {
            "files": [
                "src/**/*",
                "3d-style/**/*"
            ],
            "rules": {
                "no-restricted-syntax": [
                    "error",
                    {
                        "selector": "AwaitExpression",
                        "message": "Async/await syntax is not allowed."
                    },
                    {
                        "selector": "FunctionDeclaration[async=true]",
                        "message": "Async function declarations are not allowed."
                    },
                    {
                        "selector": "FunctionExpression[async=true]",
                        "message": "Async function expressions are not allowed."
                    },
                    {
                        "selector": "ArrowFunctionExpression[async=true]",
                        "message": "Async arrow functions are not allowed."
                    },
                    // prevent issues with esbuild/vite https://github.com/mapbox/mapbox-gl-js/issues/12656
                    {
                        "selector": "ClassProperty[value]",
                        "message": "ClassProperty values are not allowed."
                    },
                    {
                        "selector": "LogicalExpression[operator='??']",
                        "message": "Nullish coalescing is not allowed."
                    },
                    {
                        "selector": "ChainExpression",
                        "message": "Optional chaining is now allowed."
                    }
                ]
            }
        }
    ],
    "env": {
        "es6": true
    },
    "ignorePatterns": [
        "dist/**/*",
        "src/style-spec/bin/*"
    ]
}