.eslintrc.js

module.exports = {
    root: true,

    // rule presets and plugins
    extends: [
        "eslint:recommended",
        "plugin:@typescript-eslint/eslint-recommended",
        "plugin:@typescript-eslint/recommended",
        "plugin:import/recommended",
        "plugin:import/typescript",
    ],
    parser: "@typescript-eslint/parser",
    plugins: ["@typescript-eslint"],
    env: {
        es2022: true,
        browser: false,
        node: true,
        mocha: true,
    },

    // custom rules
    // see https://eslint.org/docs/latest/rules
    rules: {
        // logic
        "prefer-const": "warn",
        "no-promise-executor-return": "warn",
        "consistent-return": "warn",
        "no-unneeded-ternary": "warn",
        yoda: "warn",

        "@typescript-eslint/no-unused-vars": ["warn", { argsIgnorePattern: "^_" }],
        "@typescript-eslint/no-explicit-any": "off",
        "@typescript-eslint/ban-ts-comment": "off",

        // imports
        "import/order": [
            "warn",
            {
                alphabetize: { order: "asc", caseInsensitive: true },
                pathGroups: [{ pattern: "@klaytn/**", group: "parent", position: "after" }],
                "newlines-between": "always",
                pathGroupsExcludedImportTypes: ["@klaytn/**"],
            },
        ],

        // formatting
        curly: ["warn", "all"],
        "brace-style": ["warn", "1tbs", { allowSingleLine: true }],
        semi: "warn",
        "no-extra-semi": "warn",
        quotes: ["warn", "double", { avoidEscape: true }],
        "comma-dangle": ["warn", "only-multiline"],
        "arrow-parens": "warn",
        "wrap-iife": "warn",

        // formatting about spaces
        "max-len": ["off", 180],
        indent: ["warn", 4],
        "linebreak-style": ["warn", "unix"],

        "no-trailing-spaces": "warn",
        "no-multiple-empty-lines": "warn",
        "no-multi-spaces": "warn",
        "padded-blocks": ["warn", "never", { allowSingleLineBlocks: true }],
        "lines-between-class-members": ["warn", "always", { exceptAfterSingleLine: true }],

        "space-before-blocks": ["warn", "always"],
        "space-before-function-paren": ["warn", { named: "never", anonymous: "always", asyncArrow: "always" }],
        "space-in-parens": ["warn", "never"],
        "space-infix-ops": "warn",
        "spaced-comment": "warn",
        "no-whitespace-before-property": "warn",

        "array-bracket-spacing": "warn",
        "arrow-spacing": "warn",
        "block-spacing": "warn",
        "comma-spacing": "warn",
        "key-spacing": ["warn", { mode: "minimum" }],
        "keyword-spacing": "warn",
        "semi-spacing": "warn",
    },
    overrides: [
        {
            // tests use relaxed rules
            files: ["test/**/*"],
            rules: {
                "@typescript-eslint/no-var-requires": "off",
                // give some flexibility adding and deleting variables
                "@typescript-eslint/no-unused-vars": "off",
                "prefer-const": "off",
            },
        },
    ],
};