ESLint Config

Preconfigured ESLint rules and Prettier formatting for plug and play usage in projects.

How to use

• Install @alchemisten/eslint-config with: yarn add @alchemisten/eslint-config
• Install the required peer dependencies if not present: yarn add eslint prettier eslint-config-airbnb-typescript-prettier -D
• Use it within your .eslintrc:

  {
      "extends": "@alchemisten/eslint-config"
  }

New release

Please note, that any change to the linting rules that produces an error and not just a warning needs to be major release, because it will break dependent code.

Custom rules

These are all the rules which differ from the AirBnB config or the default Prettier settings:

ES Lint

• import/prefer-default-export: Default imports are not preferred
• no-await-in-loop: It is more common to have dependent calls in a loop than parallelizable calls
• no-cond-assign: Turned off to allow assigning in while loops
• no-console: Allowed until we have a logger package
• no-restricted-imports: Make sure all Material UI components are imported directly from core
• no-restricted-syntax: for (of) considered fast enough for our use cases, beware for (in) and check object property yourself
• no-return-await: Debugging is improved with return await at the cost of an extra microtask
• no-useless-constructor: Empty constructor required by some redux implementations
• sort-imports: Members in a multiple member import declaration should be sorted alphabetically

Typescript

• @typescript-eslint/no-unused-vars: Only produce warnings for unused variables
• @typescript-eslint/explicit-module-boundary-types: Not necessary because IntelliSense catches this in a sufficient fashion
• @typescript-eslint/explicit-member-accessibility: Require explicit accessibility declaration of all class members

Prettier

• printWidth: Print width is set to 120, instead of 80 for better readability
• semi: Semicolons are required
• singleQuote: Single quotes are used instead of double quotes in normal code
• tabWidth: Tab width is set to 4 spaces instead of 2

Further reading

• List of all ESLint rules
• AirBnB Javascript styleguide with reasoning and explanations for rules
• Prettier options