ESLint configured

Without ESLint or Biome, code quality issues — unused variables, implicit any, unsafe type assertions, missing await, console.log in production — are caught only by the developer's own review discipline rather than automatically on every commit. ISO 25010:2011 §6.5.4 classifies absent static analysis as a maintainability defect. The practical effect: every code review must manually check for issues that a linter would flag in milliseconds, and issues that slip through become permanent residents of the codebase.

Set up ESLint with TypeScript support and wire it into CI. A minimal configuration:

npm install -D eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin

// eslint.config.mjs
import tseslint from '@typescript-eslint/eslint-plugin'
import tsparser from '@typescript-eslint/parser'

export default [
  {
    files: ['**/*.ts', '**/*.tsx'],
    languageOptions: { parser: tsparser },
    plugins: { '@typescript-eslint': tseslint },
    rules: {
      ...tseslint.configs.recommended.rules,
      '@typescript-eslint/no-explicit-any': 'error',
      '@typescript-eslint/no-unused-vars': 'error',
      'no-console': ['error', { allow: ['error', 'warn'] }],
    },
  },
]

Add to package.json:

{ "scripts": { "lint": "eslint src/ --max-warnings=0" } }