eslint.js

module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint/eslint-plugin'],
  extends: [
    'plugin:@typescript-eslint/eslint-recommended',
    'plugin:@typescript-eslint/recommended',
    'prettier',
  ],
  env: {
    node: true,
    jest: true,
  },
  rules: {
    // https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin/docs/rules
    '@typescript-eslint/explicit-function-return-type': 'error',
    '@typescript-eslint/explicit-module-boundary-types': 'error',
    '@typescript-eslint/no-explicit-any': 'error',
    '@typescript-eslint/prefer-readonly': 'error',
    '@typescript-eslint/no-non-null-assertion': 'off',
    '@typescript-eslint/no-namespace': 'off',
    "@typescript-eslint/ban-types": [
      "error",
      {
        "types": {
          String: {
            message: 'Use string instead',
            fixWith: 'string',
          },
          Boolean: {
            message: 'Use boolean instead',
            fixWith: 'boolean',
          },
          Number: {
            message: 'Use number instead',
            fixWith: 'number',
          },
          Symbol: {
            message: 'Use symbol instead',
            fixWith: 'symbol',
          },
        
          Function: {
            message: [
              'The `Function` type accepts any function-like value.',
              'It provides no type safety when calling the function, which can be a common source of bugs.',
              'It also accepts things like class declarations, which will throw at runtime as they will not be called with `new`.',
              'If you are expecting the function to accept certain arguments, you should explicitly define the function shape.',
            ].join('\n'),
          },
        
          // object typing
          Object: {
            message: [
              'The `Object` type actually means "any non-nullish value", so it is marginally better than `unknown`.',
              '- If you want a type meaning "any object", you probably want `Record<string, unknown>` instead.',
              '- If you want a type meaning "any value", you probably want `unknown` instead.',
            ].join('\n'),
          },
          object: {
            message: [
              'The `Object` type actually means "any non-nullish value", so it is marginally better than `unknown`.',
              '- If you want a type meaning "any object", you probably want `Record<string, unknown>` instead.',
              '- If you want a type meaning "any value", you probably want `unknown` instead.',
            ].join('\n'),
          },
          '{}': {
            message: [
              '`{}` actually means "any non-nullish value".',
              '- If you want a type meaning "any object", you probably want `Record<string, unknown>` instead.',
              '- If you want a type meaning "any value", you probably want `unknown` instead.',
            ].join('\n'),
          }
        }
      }
    ],
    'lines-between-class-members': ['error', 'always'],
    'lines-around-comment': [
      'error',
      {
        beforeBlockComment: false,
        afterBlockComment: true,
      },
    ],
    'no-return-await': 'off',
    '@typescript-eslint/return-await': 'error',
    'no-unused-vars': 'off',
    '@typescript-eslint/no-unused-vars': [
      'error',
      {
        caughtErrors: 'none',
        args: 'none',
      },
    ],
    'no-unneeded-ternary': ['error', { defaultAssignment: false }],
    'no-await-in-loop': 'error',
  },
};