Maintenance: apply automated lint/formatting rules to packages/idempotency

[dreamorosi]

Summary

At the moment the project uses eslint to lint and apply linting and code style rules across the project.

While this has helped immensely, as the codebase and number of contributors grow, it's time to enforce automated formatting so that styling and other rules are applied automatically.

In #1430 it has been decided to add prettier to the project and this issue is part of a series of tasks aimed at doing so.

Why is this needed?

To enforce styling conventions and format the code automatically before it's committed/pushed.

Which area does this relate to?

Automation

Solution

Create the .eslintrc.js below in the directory, then fix all problems & commit.

module.exports = {
  env: {
    browser: false,
    es2020: true,
    jest: true,
    node: true,
  },
  extends: [
    'plugin:@typescript-eslint/recommended',
    'plugin:prettier/recommended',
  ],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint', 'prettier'],
  settings: {
    'import/resolver': {
      node: {},
      typescript: {
        project: './tsconfig.json',
        alwaysTryTypes: true,
      },
    },
  },
  rules: {
    '@typescript-eslint/explicit-function-return-type': [
      'error',
      { allowExpressions: true },
    ], // Enforce return type definitions for functions
    '@typescript-eslint/explicit-member-accessibility': 'error', // Enforce explicit accessibility modifiers on class properties and methods (public, private, protected)
    '@typescript-eslint/member-ordering': [
      // Standardize the order of class members
      'error',
      {
        default: {
          memberTypes: [
            'signature',
            'public-field',
            'protected-field',
            'private-field',
            'constructor',
            'public-method',
            'protected-method',
            'private-method',
          ],
          order: 'alphabetically',
        },
      },
    ],
    '@typescript-eslint/no-explicit-any': 'error', // Disallow usage of the any type
    '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }], // Disallow unused variables, except for variables starting with an underscore
    '@typescript-eslint/no-use-before-define': ['off'], // Check if this rule is needed
    'no-unused-vars': 'off', // Disable eslint core rule, since it's replaced by @typescript-eslint/no-unused-vars
    // Rules from eslint core https://eslint.org/docs/latest/rules/
    'array-bracket-spacing': ['error', 'never'], // Disallow spaces inside of array brackets
    'computed-property-spacing': ['error', 'never'], // Disallow spaces inside of computed properties
    'func-style': ['warn', 'expression'], // Enforce function expressions instead of function declarations
    'keyword-spacing': 'error', // Enforce spaces after keywords and before parenthesis, e.g. if (condition) instead of if(condition)
    'padding-line-between-statements': [
      // Require an empty line before return statements
      'error',
      { blankLine: 'always', prev: '*', next: 'return' },
    ],
    'no-console': 0, // Allow console.log statements
    'no-multi-spaces': ['error', { ignoreEOLComments: false }], // Disallow multiple spaces except for comments
    'no-multiple-empty-lines': ['error', { max: 1, maxBOF: 0, maxEOF: 0 }], // Enforce no empty line at the beginning & end of files and max 1 empty line between consecutive statements
    'no-throw-literal': 'error', // Disallow throwing literals as exceptions, e.g. throw 'error' instead of throw new Error('error')
    'object-curly-spacing': ['error', 'always'], // Enforce spaces inside of curly braces in objects
    'prefer-arrow-callback': 'error', // Enforce arrow functions instead of anonymous functions for callbacks
    quotes: ['error', 'single', { allowTemplateLiterals: true }], // Enforce single quotes except for template strings
    semi: ['error', 'always'], // Require semicolons instead of ASI (automatic semicolon insertion) at the end of statements
  },
};

Acknowledgment

• This request meets Lambda Powertools Tenets
• Should this be considered in other Lambda Powertools languages? i.e. Python, Java, and .NET

Future readers

Please react with 👍 and your use case to help us understand customer demand.

[dreamorosi]

Marking this issue as blocked until #1442 is merged - we should address this then.

[github-actions]

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[github-actions]

This is now released under v1.9.0 version!