Best Practices & Anti-patterns

Key principles

DO: extend shared configs, prefer warn before error when adopting, commit configs to git. DON'T: switch off core rules, ignore formatter conflicts, skip CI checks.

Good vs bad patterns

Compare good and bad ESLint configuration patterns.

// GOOD: shared config, specific overrides, gradual severity
export default [
  js.configs.recommended,
  prettier,
  { files: ['**/*.test.js'], rules: { 'no-console': 'off' } },
  { rules: { 'no-console': 'warn' } },
];

// BAD: switch off core rules wholesale
export default [{ rules: { 'no-unused-vars': 'off', 'no-undef': 'off' } }];

// BAD: strict errors on day one
export default [{ rules: { 'no-console': 'error' } }];

Output:

Good patterns use extends, overrides, and warn initially

Evolution over time

Start loose (warn, few rules) and tighten over time (error, more rules) as the team adapts. This reduces friction and improves adoption.

Quick check

Quick check: What's a best practice for team adoption?

• Enforce all rules as errors immediately.
• Disable most rules.
• Start with warn, gradually move to error as team adapts.
• Skip CI checks